How US defense secretary Hegseth circumvents the official DoD communications equipment

(Updated: June 10, 2025)

US defense secretary Pete Hegseth appears to have a private computer in his office that is linked to the public internet. He wanted this computer to use the messaging app Signal, which is the preferred method of communication among Trump's government officials.

Here I will look at the secretary of defense's official communications equipment and the SecDef Cables communications center. There's also a photo in which Hegseth's private computer can be recognized.

US defense secretary Pete Hegseth in his office in the Pentagon, January 30, 2025
(Still from a video message on X, formerly Twitter)

Hegseth's government equipment

Like his predecessors, Trump's defense secretary Pete Hegseth has access to a range of secure and non-secure telephone and computer networks. The equipment is installed at a table behind his back, when sitting at his big writing desk in the Pentagon.

In the photo above we can see that equipment in a set-up that has basically been unchanged since Chuck Hagel, who was Obama's secretary of Defense from 2013 to 2015. In the photo of Pete Hegseth we see from left to right:

- On top of a wooden stand sits a Cisco IP Phone 8841 with a 14-key expansion module. This phone is part of the Crisis Management System (CMS), which connects the most senior government officials, including the President, the National Security Council, Cabinet members, the Joint Chiefs of Staff, and others. Its bright yellow bezel indicates that it can be used for conversations up to Top Secret/Sensitive Compartmented Information (TS/SCI).

- Below the CMS phone on the wooden stand is (hardly visible) an Integrated Services Telephone-2 (IST-2), which can be used for both secure and non-secure phone calls. This phone belongs to the Defense Red Switch Network (DRSN), also known as the Multilevel Secure Voice service. It's the main system for classified military conversations and connects the White House, all military command centers, intelligence agencies and NATO allies.

- Right in front of the IST-2 is another Cisco IP Phone 8841 with a 14-key expansion module, but this time with a green bezel, which indicates that it's for unclassified phone calls. This phone is part of the internal telephone network of the Pentagon. It replaced an Avaya Lucent 6424 executive phone, which can be seen in the following photo from 2021, along with a better view on the other phones:

Former secretary of defense Lloyd Austin in his Pentagon office in 2021,
with a Cisco IP phone with yellow bezel for the CMS and
an IST-2 phone with many red buttons for the DRSN.
(DoD photo - click to enlarge)

- Besides the telephones there are two computer screens, both with a bright green wallpaper, which again indicates that they are connected to an unclassified network, most likely NIPRNet. In the photo of Lloyd Austin's office we see that there's also a KVM switch which is used to switch securely to the SIPRNet (Secret) and JWICS (Top Secret/SCI) networks, using the same keyboard, video and mouse set.

- Finally, at the right side of the table there are two Cisco Webex DX80 videoteleconferencing screens. The one at the right has a yellow label, which indicates that it's approved for Top Secret/SCI and likely also belongs to the aforementioned Crisis Management System (CMS), more particularly as successor of the Secure Video Teleconferencing System (SVTS). The other screen might then be for videoconferences at a lower classification level.

> See also: US military and intelligence computer networks

Hegseth's personal computer

Despite the wide range of options for communicating via the proper and secure government channels, secretary Hegseth insisted on using Signal. Apparently it wasn't allowed or possible to install this app on one of the government computers, nor on a smartphone that is approved for classified conversations.

Therefore, Hegseth initially went to the back area of his office where he could access Wi-Fi to use Signal, according to AP News. It's not clear whether he used a private laptop or his personal smartphone, both of which would have been strictly forbidden to use in secure areas like this.

> See: The equipment that Trump's national security team should have used

Somewhat later, Hegseth requested an internet connection to his desk where he could use a computer of his own. This line connects directly to the public internet and bypassed the Pentagon's security protocols. Hegseth's new computer must be the one that can be seen in the photo below, as it wasn't there yet on February 21 and has no labels that indicate its classification level:

US defense secretary with a new desktop computer on his desk, March 20, 2025
(DoD photo, see also this video message on X)

Some other employees at the Pentagon also use direct lines to the public internet, for example when they don't want to be recognized by an IP address assigned to the Pentagon. That's risky because such a line is less well monitored than NIPRNet, which allows limited access to the outside internet.

At his new desktop computer, Hegseth had Signal installed, which means he effectively 'cloned' the Signal app that is on his personal smartphone. He also had interest in the installation of a program to send conventional text messages from this personal computer, according to some press sources.

The move was intended to circumvent a lack of cellphone service in much of the Pentagon and enable easier communication with the White House and other Trump officials who are using the Signal app.

Update: Ultimately on May 5, 2025, the new, unauthorized computer had apparently been removed, at least from secretary Hegseth's desk, as can be seen in this video that was published on X (formerly Twitter).

SecDef Cables

It is remarkable to what great lengths Hegseth went to use the Signal app, because as defense secretary he has his own communications center which is specialized in keeping him in contact with anyone he wants. This center is commonly called SecDef Cables and is part of Secretary of Defense Communications (SDC) unit.

SecDef Cables provides operational information management and functions as a command and control support center. It is staffed by 26 service members and 4 civilians. They provide "comprehensive voice, video, and data capabilities to the secretary and his immediate staff, regardless of their location, across multiple platforms and classifications."

Furthermore, SecDef Cables serves as a liaison to the National Military Command Center (NMCC), the White House Situation Room, the State Department Operations Center and similar communication centers. Finally, Cables manages the connections for the Defense Telephone Link (DTL), which is a lower-level hotline with military counterparts in about 25 countries, including Russia and China.

> See also: Bilateral Hotlines Worldwide

Secretary of Defense Communications recruitment video from 2023

Links and sources
- emptywheel: Whiskey Pete’s Dirty Desktop (April 25, 2025)
- AP News: Hegseth had an unsecured internet line set up in his office to connect to Signal, AP sources say (April 24, 2025)
- The Washington Post: Hegseth had Signal messaging app installed on an office computer (April 24, 2025)

See also the comments on Hacker News

The equipment that Trump's national security team should have used

(Updated: May 2, 2025)

Recently, the editor in chief of The Atlantic found himself in a group chat on Signal, in which president Trump's national security team discussed a military operation in Yemen. This immediately became SignalGate.

Here I present the secure government equipment and networks that Trump's team should have used instead of an app on their (personal) smartphones. It will also become clear why the Trump team prefers using Signal.

From left to right: Marco Rubio, Michael Waltz and Pete Hegseth in a White House conference room,
with some screenshots of messages that were exchanged in the Signal group chat.
(White House photo, January 28, 2025 - click to enlarge)

The Houthi PC small group

On March 11, 2025, president Trump's national security adviser Michael Waltz started a group chat on the open-source encrypted messaging app Signal to discuss airstrikes on Houthi rebels in Yemen, which took place on March 15.

The chatgroup was named "Houthi PC small group", with PC apparently referring to Principals Committee, a term typically used for a gathering of senior national-security officials. This group had a total of 19 participants:

- Michael Waltz, National Security Adviser
- Brian McCormack, Chief of Staff for the National Security Council
- Alex Wong, Principal Deputy National Security Adviser
- Susie Wiles, White House Chief of Staff
- Stephen Miller, White House Deputy Chief of Staff for Policy
- JD Vance, Vice-President of the United States
- Marco Rubio, Secretary of State
- Mike Needham, Special Adviser for the Department of State
- Pete Hegseth, Secretary of Defense
- Scott Bessent, Secretary of the Treasury
- Dan Katz, Chief of Staff for the Secretary of the Treasury
- Tulsi Gabbard, Director of National Intelligence
- Joe Kent, Acting Chief of Staff for the Director of National Intelligence
- John Ratcliffe, Director of the CIA
- Walker Barrett, Staff member of the House Armed Services Committee Republicans
- Steve Witkoff, Special Envoy to the Middle East
- Jacob, function unknown
- Jeffrey Goldberg, Editor in Chief of The Atlantic

This list shows that the members of the "Houthi PC small group" were from many different government departments and agencies and that some lower-ranking officials participated as well.

This is probably one of the reasons why they used Signal: given the variety of positions, they would probably not have access to the same equipment and/or networks to have a properly secured conversation.

The major US government departments and intelligence agencies have their own computer networks, usually one for unclassified and one or two for classified information:

Overview of major Homeland Security computer networks
From a briefing for Congress, July 2004

Secure computer networks

The networks of the Department of Defense (DoD) are the most widely used and therefore most suitable for interagency communications. There are separate DoD networks for different classification levels:

NIPRNet (Non-secure Internet Protocol Router Network)
- For information that is Sensitive But Unclassified (SBU)
- Circa 4,000,000 users

SIPRNet (Secret Internet Protocol Router Network)
- For information classified Secret (S)
- Circa 500,000 users

JWICS (Joint Worldwide Intelligence Communications System)
- For information classified Top Secret/SCI (TS/SCI)
- Circa 200,000 users

These classified networks are not connected to the internet and additionally secured with TACLANE network encryptors. These networks offer email (in the Signal group chat mentioned as "high side inboxes"), messaging and other collaboration tools, but they can also be used for VoIP phone calls and secure video teleconferencing.

> See also: US military and intelligence computer networks

Operations center in the US Central Command headquarters, with computers and
VoIP phones for Unclassified (green) and Secret (red) communications.
(still from 60 Minutes, January 2021 - click to enlarge)

Secure telephone networks

The DoD also operates a secure telephone network for classified conversations, called the Defense Red Switch Network (DRSN), also known as the Multilevel Secure Voice service. The DRSN connects the White House, all military command centers, intelligence agencies, government departments and NATO allies.

The DRSN has some special features and uses custom made telephone sets (currently the IST-2 made by Telecore), which can be used for both secure and non-secure phone calls. These phones also have the distinctive four red buttons for Multilevel Precedence and Preemption (MLPP).

During the attacks of September 11, 2001, the DRSN didn't function as intended and therefore a new Crisis Management System (CMS) was established. This includes a dedicated Voice over IP network that connects the President, the National Security Council, Cabinet members, the Joint Chiefs of Staff, intelligence agency watch centers, and others.

The CMS uses high-end Cisco IP phones with a bright yellow bezel. This color indicates that it can be used for conversations up to Top Secret/Sensitive Compartmented Information (TS/SCI), which is the classification category for the most sensitive, intelligence related information.

Former secretary of defense Lloyd Austin in his Pentagon office in 2021,
with a Cisco IP phone with yellow bezel for the CMS and
an IST-2 phone with many red buttons for the DRSN.
(DoD photo - click to enlarge)

Most senior members of the "Houthi PC small group" have a phone for the CMS in their office, but their deputies, advisers and staff members usually have not. So when they have to be involved in a secure phone call, that often means they have to be in the same room as their principal and listen to the conversation via the speakerphone.

It's noteworthy that not included in the Signal chat group were Michael E. Kurilla, commander of the US Central Command, and local commanders who led the military operation in Yemen. They were likely in contact with defense secretary Hegseth via the proper military channels, which would be SIPRnet or the DRSN.

> See also: The communications systems at the US Central Command headquarters

Securing mobile phones

All the equipment for secure communications discussed so far are fixed/landline devices that sit on someone's desk. That's fine when working in office, but nowadays people are used to do almost everything on their smartphone.

Securing mobile communications has long been a challenge. In the first place because outside, conversations can easily be overheard. For a long time, encryption devices were large and heavy, until in 2002 the Sectéra Secure Wireless Phone was introduced, which enabled encrypted phone calls and SMS/text messages over public networks.

> See also: How Obama's BlackBerry got secured

> See also: Obama using a secure GSM phone

Around 2010, cell phones of the GSM generation were rapidly replaced by smartphones, which became so complex that it's very difficult, if not impossible to prevent the device from being compromised by malware and/or backdoors.

Under its Commercial Solutions for Classified (CSfC) program, the NSA tried to solve this problem by securing commercially available devices with multiple layers of protection and encryption. This resulted in the DoD Enterprise Mobility program, which encompasses three different classification levels:

DMUC (Unclassified)
- For Samsung and Apple smartphones and tablets
- Circa 140,000 users

DMCC-S (Secret)
- For Samsung smartphones and tablets
- Circa 8000 users

DMCC-TS (Top Secret)
- For Samsung smartphones
- Circa 500 users

Overview of the DoD Enterprise Mobility program, 2022
(click here for the full document)

The CellCrypt app

The Secret version (DMCC-S) became operational in 2015 and offers secure phone calls via the CellCrypt app, access to SIPRNet email via the Outlook Web Application (OWA) and some other pre-approved apps on a Samsung smartphone or a Samsung tablet.

The website of the manufacturer provides additional details about the encryption methods used by CellCrypt app and also says that it can also be used for secure instant messaging, including group messaging and sharing photos, videos, voice notes, and files of any kind.

The DMCC-S solution has further restrictions, because in case the phone not only handles data-in-transit (DIT), but also stores classified information (data-at-rest, or DAR) it may only be used in physically protected environments.

On social media some people claimed that a conversation like in the Signal group chat should only take place in a Sensitive Compartmented Information Facility (SCIF). However, a SCIF is only mandatory for information classified Top Secret/SCI, while military information is usually classified Secret.


At the White House

The White House provides its employees with Apple iPhones, but without access to the iOS App Store and with all text messaging capabilities disabled - under president Biden, only a few staffers in the press office had the ability to text on a limited basis.

Especially Signal's option for "disappearing messages" (which was turned on in the "Houthi PC small group") isn't compliant with the Presidential Records Act (PRA), which requires that all communications by and among White House staff members have to be archived.

The phones issued to White House officials are managed by the Presidential Information Technology Community (PITC), which is an umbrella organization established in 2015 to provide IT systems to the President, Vice President, the National Security Council, the Secret Service, the White House Communications Agency, and others.



Trump's shift to Signal

As we have seen, there are various highly secure communication channels that Trump's national security team could have used. Those who were working in their office had access to secure computer networks and a secure phone, those who were traveling (like Gabbard and Witkoff) had the option of using a DMCC-S smartphone.

However, it already was the transition team that prepared Trump's take-over of the presidency in January 2025, which deliberately refused to use government facilities and IT systems. This was in part to avoid the mandatory record-keeping that comes with using official resources (it's not clear why they prefer Signal, because Whatsapp has disappearing messages as well).

Instead, Trump's staffers and incoming government officials communicated via their personal devices, often using the Signal app, and this continued after Donald J. Trump had been inaugurated as the 47th president of the United States.

Last February, political appointees at the DoD ordered that Signal had to be installed on government phones for newly installed senior military officials: "they all use Signal and need it to communicate with the White House" - even though in the same month, the NSA had warned against vulnerabilities in using Signal.

NSA bulletin about Signal vulnerabilities, February 2025
(click here for the full document)

During a House Intelligence Committee hearing a few days ago, Trump's CIA director John Ratcliffe said that Signal is also widely used by officials and staff at his agency's headquarters: "One of the first things that happened when I was confirmed as CIA director was Signal was loaded onto my computer at the CIA as it is for most CIA officers."

National Security Council spokesperson Brian Hughes said that Signal is allowed on government devices and that some agencies automatically install it on employees’ phones. "It's one of a host of approved methods for unclassified material with the understanding that a user must preserve the record" according to Hughes.

Updates:

On April 1, 2025, The Washington Post reported that Michael Waltz and other members of the National Security Council (NSC) also used Gmail for work-related communications. One of Waltz's senior aides, for example, used Gmail for "highly technical conversations with colleagues at other government agencies involving sensitive military positions and weapons systems."

On April 2, 2025, Politico revealed that the team of national security adviser Mike Waltz had set up at least 20 group chats on Signal to coordinate official work on issues including Ukraine, China, Gaza, Middle East policy, Africa and Europe.

On April 6, 2025, The Guardian reported that an internal investigation by the White House made clear how Jeffrey Goldberg was accidentally added to the Signal group chat: in October 2024, Goldberg had emailed the Trump campaign and his email was forwarded to Trump's former spokesman Brian Hughes. The latter copied and pasted the content of the email, including the signature block with Goldberg's phone number, into a text message that he sent to Michael Waltz. Waltz' iPhone then semi-automatically stored Goldberg's number under the contact card for Hughes, who had now become the spokesman for the National Security Council. So when Waltz set up the "Houthi PC small group" on Signal, he actually wanted to add Hughes, but this resulted in the number of Goldberg being added.

On April 20, 2025, the New York Times reported that Hegseth also shared similar details about the Yemen operation in another Signal group that included his wife Jennifer, his brother Phil, and his personal lawyer Tim Parlatore. Jennifer Hegseth has no relevant role in the Defense Department, while Phil Hegseth serves in the Pentagon as a Department of Homeland Security appointee. Parlatore, a military defense attorney, recently rejoined the Navy with an assignment to improve military justice issues.

On May 1, 2025, it was reported that president Trump removed national security advisor Michael Waltz and his principal deputy Alex Wong from their functions. Waltz would be nominated as US ambassador to the United Nations.

Links and sources
- The Guardian: Exclusive: how the Atlantic’s Jeffrey Goldberg got added to the White House Signal group chat (April 6, 2025)
- Politico: Waltz’s team set up at least 20 Signal group chats for crises across the world (April 2, 2025)
- Bruce Schneier: The Signal Chat Leak and the NSA (March 31, 2025)
- The Independent: Previous administrations were wary of the messaging app Signal. Trumpworld has embraced it (March 27, 2025)
- The Atlantic: Here Are the Attack Plans That Trump’s Advisers Shared on Signal (March 26, 2025)
- The Atlantic: The Trump Administration Accidentally Texted Me Its War Plans (March 24, 2025)
- TWZ: C-17’s ‘Silver Bullet’ Airstream Trailer Pod Used By Secretary Of Defense Hegseth On First Overseas Trip (February 12, 2025)
- DoD Inspector General: Audit of Cybersecurity of DoD Classified Mobile Devices (December 13, 2024)

See also the comments on Hacker News

The phones of US Director of National Intelligence James Clapper

One of the key players during the Snowden affair was Director of National Intelligence James Clapper. He is responsible for coordinating all 16 American intelligence agencies, a role which is reflected by the number and the types of telephone equipment in his office.

Clapper has six phones, more than for example the director of the NSA, or the Defense Secretary. Here we will take a close look at these telecommunication devices used by the US Director of National Intelligence.


The office of Director of National Intelligence (DNI) was created in 2004, after the 9/11 Commission Report recommended a stronger and separate leadership for the US intelligence community. Before, it was the director of the CIA who acted as Director of Central Intelligence (DCI) in order to coordinate the various intelligence agencies.

Australian foreign affairs minister Kevin Rudd (right) meeting DNI James Clapper (left)
(Photo: Australian Foreign Affairs Department - Click to enlarge)

The telecommunications equipment used by DNI James Clapper can be seen in a picture from September 17, 2010, which shows his office in the headquarters building of the Office of the Director of National Intelligence (ODNI) at the Liberty Crossing compound near Tyson’s Corner, Virginia, while he was visited by the Australian Minister for Foreign Affairs, Kevin Rudd.

When we take the high resolution version of the picture above, we can see that the displays and buttons of all the phones behind the DNI's desk are blurred by a censor. Apparently there's some rule for that, because from this distance it would be impossible to read anything.

Close-up of the telecommunications equipment behind the desk of DNI James Clapper.

IST-2 phone

The first phone on the left side is an Integrated Services Telephone version 2 (IST-2), which was designed by Raytheon and subsequently manufactured by Telecore, a small company that took over the production of these devices.

The IST is a so called "red phone", which means that it's connected to the Defense Red Switch Network (DRSN). This is the main secure telephone network for military command and control communications and connects all mayor US command centers and many other military facilities.

Like previous red phones made by Electrospace Systems Inc. (ESI), the IST-2 allows to make both secure and non-secure calls through this one single device. The phone itself has no encryption capability: any secure calls are encrypted in bulk before leaving the secure building, enclave or compound.

As part of a military telephone network, the IST-2 also has the distinctive 4 red buttons which are used to select the four levels of a system called Multilevel Precedence and Preemption (MLPP). This allows to make phone calls that get precedence over ones with a lower priority.

VoIP phones

Next, there are three Cisco 7975 unified IP phones, which belong to the most widely used high-end office phones. These phones have no encryption capability, but they can easily be used as part of dedicated and secure Voice-over-IP networks.

The first Cisco phone, next to the IST-2, seems to have a bright green label, indicating that it has to be used for unclassified phone calls. Probably this phone is part of the internal non-secure telephone network of the Office of the Director of National Intelligence (ODNI).

The second Cisco phone, right of the computer screen, has no recognizable label. It can be part of any secure or non-secure telephone network which DNI Clapper needs to have access to. One option could be the National Secure Telephone System (NSTS), which is used by the signals intelligence community (i.e. NSA).

The third Cisco phone has a distinctive bright yellow faceplate instead of the standard silver one. This indicates that it's part of the highly secure Executive Voice over Secure IP-network, which connects the President with senior cabinet members and some other high-level government officials.

This top-level telephone network was set up in 2007-2008. Before, the President was connected to the general military DRSN, but during the attacks of 9/11, this network appeared to be not reliable enough.

It's this bright yellow Cisco phone that shows that the Director of National Intelligence has direct access to the President. As we have seen earlier, even the director of NSA doesn't have this kind of telephone, and therefore lacks a direct line to the President.

> See also: NSA director Alexander's phones - US State Department red phones

STE phones

The last type of telephone we see in Clapper's office are two big black phones called Secure Terminal Equipment (STE). These are made by the American defense contractor L3 Communications and are highly secure devices capable of encrypting calls up to the level of Top Secret/SCI.

STE phones can be used to make secure calls to anyone with a similar or compatible device and there are an estimated 400.000 STE users. STE is the successor of the almost legendary STU-III secure phone system from the late 1980s.

These STE phones can be used for secure communications with everyone working for the US government, the military, its contractors, and also foreign partners who can not be reached through a more select secure telephone network, like the DRSN or the NSTS.

Videoteleconferencing

Besides the six telephones, DNI Clapper also has two videoteleconferencing (VTC) screens behind him. In the first picture we saw a white videoconferencing screen at the far right, and another picture, from a different angle, shows another VTC screen standing at the far left side:

A black Tandberg Centric 1700 MXP VTC screen behind DNI James Clapper.
(Photo: ODNI)

Both these VTC screens have a high-definition camera and are made by the Norwegian manufacturer Tandberg. In 2010 this company was bought by Cisco Systems, so their equipment can be safely used for classified US videoconferencing purposes.

Maybe one of the sets in Clapper's office is used for unclassified, and the other for classified videoconferencing, but it's also possible that both are used for secure video connections but at different classification levels.

At least one of the VTC screens will be used for Top Secret/SCI Videoconferencing, which is for users within the intelligence community. From within secured locations (SCI enclaves), this video feed goes over the JWICS-network, which is secured by stream-based Type 1 bulk encryption devices.



Computer

Finally, there's also one computer screen standing in the midst of the telephones. Below is a keyboard and likely there's also a KVM-switch to enable access to multiple physically separated networks through a single "Keyboard, Video and Mouse" set.

For US intelligence officials, such a KVM-switch usually provides access to NIPRNet or DNI-U (Unclassified, for general purposes), SIPRNet (Secret, for military and intelligence purposes) and JWICS (Top Secret/SCI, for intelligence purposes).

> See also: US military and intelligence computer networks

Update:
James Clapper resigned as Director of National Intelligence on January 20, 2017, the same day that the new president Donald Trump was inaugurated.

A mysterious Tektron secure telephone

(Updated: March 17, 2017)

Recently, a mysterious telephone was offered for sale at eBay. The device was made by the little-known company Tektron Micro Electronics, Inc. from Hanover, Maryland, and seems to be a secure phone for military use.

Apart from the pictures shown below, nothing more is known about it, but maybe some readers of this weblog recognize the device and have some more information about its purpose and where it was used (see the update!)

A Tektron secure military telephone
(Photo via eBay - Click to enlarge)

The phone comes without a handset, but it has a display and a common 12-button key pad, with some additional special purpose buttons. According to the seller, all of them are made of some kind of rubbery material instead of hard plastic. The big round buttons reveal that this is a secure phone, capable encrypting the calls: a green button with a green light for Secure and a red button with a (probably) red light for Non-Secure:

Keypad of the Tektron telephone
(Photo via eBay - Click to enlarge)

It seems the small button with "2nd" can be used to select the functions which are marked in blue above the standard buttons. Most interesting are the FO (Flash Override) designation above the "3", the F (Flash) above the "6", the I (Immediate) above the "9" and the P (Priority) above the "#" button.

FO, F, I, and P designate the four levels of a system called Multilevel Precedence and Preemption (MLPP), which allows to make phone calls that get precedence over ones with a lower priority. Flash Override (FO) was designed to allow the US President and the National Command Authority to preempt any other traffic in the network in case of a national military emergency.

This precedence system only works on telephone networks that allow this special capability, like the AUTOVON network that was used by the US military (since 1982 replaced by the Defence Switched Network). One of the characteristics of the AUTOVON network was that most of its phones were equipped with a standardized keypad with four extra red buttons for the precedence levels:

The standard AUTOVON keypad
(Click to enlarge)

So apparently, the Tektron phone was intended for use on the military telephone network, but why it doesn't have the standard AUTOVON keypad is a mystery.

We also don't know when the phone was manufactured. The only indication is provided by the label on the back of the device. It says the model number is EXT-4Rx and has the serial number 271/4.0. The seller had a second device with serial number 111.

There is also a National or NATO Stock Number (NSN): 5810-01-357-8193. Looking up this number on a stock number website returns a "Date Established" of 1992. This indicates the phone must be somewhere from the 1990s, although the way this number is placed, without its own line, also looks like it could have been added later on:

Label of the Tektron telephone
(Photo via eBay - Click to enlarge)

It's not known where exactly this phone was used, which is an even bigger question because in the 1990s secure telephony for the US government and military had largely been standardized after the introduction of the STU-III family of secure voice products.

The STU-III standard was introduced by the NSA in 1987, and three manufacturers were allowed to produce secure telephones based on this standard:

- Motorola
- AT&T (later: Lucent Technologies > General Dynamics)
- RCA (later: General Electric > Lockheed Martin > L3-Communications)

Motorola and AT&T each made a few hundred thousand of these devices. Tektron is not known for having participated in the STU-III program.

Side view of the Tektron secure military telephone
(Photo via eBay - Click to enlarge)

The Tektron secure phone measures 7.75 inches (19,6 cm) wide, a little over 9 inches tall (22,8 cm) and 2 inches (5 cm) thick. The encryption function made it very heavy: it weighs about 5,5 pounds (2,5 kg), as the case is fully made from cast non-metallic metal, perhaps aluminum.

Such a metal encasing prevents electromagnetic radiation from being intercepted from the outside (TEMPEST). The STU-III, and the newer STE phones only have their bottom part out of metal, with the upper part out of plastic.
 

Update:

Meanwhile, a photo was found showing that the mysterious Tektron phone was actually used aboard the E-4B aircraft, which is a highly modified Boeing 747-200, officially known as the National Airborne Operations Center (NAOC). As such, the plane has robust and sophisticated communications equipment as well as the capability to be refueled in flight.

In the photo below, we see two Tektron phones aboard the E-4B on July 24, 2005, during a trip of Defense Secretary Donald H. Rumsfeld to Central Asia and Iraq:

Two Tektron telephones aboard the E-4B aircraft
(photo: Gerry J. Gilmore - click to enlarge)

As can be seen in the following video tour inside an E-4B aircraft, the Tektron phones were replaced by a modified smaller version of the Integrated Services Telephone (IST), made by Raytheon. These phones were seen on the aircraft already in 2008. Unlike the Tektron phone, the IST itself has no capability to encrypt the calls - that's done centralized at the local switch, in this case likely by a central network encryptor.

Currently, there are black telephone units with a large touch screen installed aboard the E-4B, as can be seen in pictures from inside the aircraft during defense secretary Ash Carter's trip to Japan on April 6, 2015. These phones could be custom-made by Telecore, Inc., a small company that also manufactures the IST-2 telephone for the secure defense network.

US State Department red phones

(Updated: March 7, 2017)

On February 1st, senator John Kerry became the new US Secretary of State, succeeding Hillary Clinton, who held this office since January 2009. John Kerry is just two weeks in office, but we already have a nice picture of him in his new office:

U.S. Secretary of State John Kerry speaks by telephone with
UN Secretary-General Ban Ki-moon from his Inner Office
at the Department of State, February 5, 2013.
(State Department photo)

This picture is taken in the so called inner or private office, which is next to the bigger ceremonial office, where the secretary of state is most often seen, receiving and talking to his guests. The smaller private office is used for the actual work, and therefore that's also where the phones are (the US president also has a rarely seen private office, next to the ceremonial Oval Office).

On the desk we see a Cisco 7975 unified IP phone with a 7916 expansion module. With a close look we can see that the phone has a yellow faceplate, instead of the standard silver one, which indicates that it's part of the new, highly secure Executive Voice over Secure IP-network. This network connects the president with all major decision makers.

The phone which secretary Kerry is using in the picture, is a high end Avaya/Lucent 6424D phone set, which is part of the internal State Department telephone network. This phone can also be seen in many pictures of the ceremonial office. Finally, we see a really large videoteleconferencing (VTC) screen with camera on top.

Updates:

From the FBI investigations in the case of former secretary of state Hillary Clinton using a private e-mail server for government business, we learn that the secretary of state's suit of offices on the 7th floor of the State Department building, known as "Mahogany Row", is secured as a Sensitive Compartmented Information Facility (SCIF).
Within that area, the bureau of Diplomatic Security (DS) has a post called Post 1, where secretary Clinton's BlackBerry was kept in a desk drawer. State Department personnel was not allowed to bring their mobile devices into Post 1 or the SCIF. Clinton had no computer in her office, but she used to check her e-mail using a personal BlackBerry or a personal iPad on the building's 8th floor balcony outside the SCIF.
SCIF's were also created in Clinton's Whitehaven residence in Washington, D.C. and her home in Chappaqua, NY, but both rooms were not always secured, with doors left open and assistants bringing their personal laptops inside.

It was also reported that secretary Clinton preferred to read documents on paper rather than on a screen, so e-mails and other files were often printed out and provided to her either at her office or home, where they were delivered in a diplomatic pouch by a security agent.
However, her deputy chief of staff Huma Abedin, like many State Department officials, found the government networks to be cumbersome, making printing documents there troubling. As a result, she sometimes transferred e-mails from her unclassified State Department account to either her Yahoo account, or her account on Clinton’s private server, and printed the e-mails from there.

After Donald Trump became president of the United States in January 2017, rooms on Mahogany Row were rebuilt to create an "office space for a new team and a new concept of how State’s nerve center would function" - a concept that wasn't shared with most State Department people though.

It seems the Cisco phone and the VTC-screen are installed quite recently, because when former secretary of state Hillary Clinton showed her inner office in May 2010, there was at least one other type of phone, which was there already when Madeleine Albright held this office:

Video still of former Secretary of State Hillary Clinton showing her
private office to Scott Pelley of the CBS show 60 Minutes.
(click to watch the video!)

Former Secretary of State Madeleine Albright in her private office
(Date unknown)

In both these pictures, we see a big white Integrated Services Telephone (IST) at the lower right corner of the bookshelfs. This futuristic looking phone was designed by Electrospace Systems Inc. and later on produced by Raytheon. It was part of the Defense Red Switch Network (DRSN), which is the main secure telephone network of the US military.

As we saw in an earlier posting, the president had a newer version of this phone, the IST-2, on his desk in the Oval Office. In 2011 that phone was also replaced by a Cisco 7975 IP phone, just like the one which is now at the desk of the secretary of state. So it looks like these new IP phones of the top secret executive VoIP network are gradually replacing the so called red phones of the DRSN, which is still an old fashioned switched telephone network.

The phones of the Defense Red Switch Network are sometimes called "red phones", because in the sixties and seventies, the telephone sets connected to predecessors of this network were often red. A nice example of such an early day red phone is the one in this picture:

This is a very common phone without rotary dial, made by ITT. Phones like this are still available today, for example for hotlines or emergency lines of any kind. This phone was probably used for a predecessor of the DRSN, like the Automatic Secure Voice Communications Network (AUTOSEVOCOM). This is indicated by the label, which says: "Up to TOP SECRET Information may be processed on this system" with next to it, the eagle from the seal of the United Stated and the words "Bureau of Diplomatic Security":

The Bureau of Diplomatic Security (DS) is an agency of the State Department, which is responsible for protecting US embassies and diplomatic personnel and securing critical information systems, like for example the telephone networks.

Therefore, the red telephone in the picture was probably used for a secure telephone connection at one of the major embassies, at the State Department operations center, or maybe even in the office of the secretary of state of that time!



Links
- 1916-2016: History of the Bureau of Diplomatic Security of the United States Department of State
- Washington Examiner: 21 things we learned from the FBI notes on Clinton's emails

Bilateral Hotlines Worldwide

(Updated: November 13, 2024)

In a previous article we discussed the Washington-Moscow Hotline, being the most famous bilateral hotline. It was soon followed by direct communication links between a number of other countries with nuclear capabilities.

In general these hotlines started as a teletype connection, being upgraded with facsimile units in the eighties and were eventually turned into dedicated secure computer networks. An exception is the hotline between Washington and London, which was a phone line already since 1943.

Overview of the top level bilateral hotlines worldwide
(Click to enlarge)

The hotlines between the heads of governments, are meant to prevent (nuclear) war in times of severe crisis. For preventing misunderstandings and miscommunications in less critical situations, countries have also set up lower level telephone hotlines between their defense or foreign ministers. For example, the United States has so called Defense Telephone Links with at least 23 other states.

Overview of the lower level bilateral hotlines worldwide
reflecting political and military relationships between countries
(Click to enlarge)

UNITED STATES - RUSSIA

- In 1963 the United States and the Soviet Union established the Direct Communications Link (DCL) or Washington-Moscow Hotline. This highly secured connection originally used teletype machines, which were replaced by facsimile units in 1988 and is using e-mail since 2008.

> Read more: The Washington-Moscow Hotline

- In 1990 both countries agreed to establish a direct, secure telephone link between Washington and Moscow, which is officially called the Direct Voice Link (DVL) and is maintained by the White House Communications Agency.

- In 2008, Russia and the United States agreed to set up a Direct Secure Communications System, which is an encrypted computer network for both the original Hotline and the Direct Voice Link. Since 2013 this network is also used for a voice link to manage cybersecurity incidents and in December 2021, for a secure video call between the Russian and the American presidents.

> Read more: From the Hotline to the first video call
between presidents Biden and Putin

The Washington-Moscow Hotline terminal room at the Pentagon in 2013
(photo: www.army.mil)

Between the United States and Russia there are also the following lower level communication links:

- In 1988 the Nuclear Risk Reduction Center (NRRC) was established at the US Department of State, which is used to exchange information in support of arms control treaties. After the split-up of the Soviet Union this secure data exchange connection, called Government-to-Government Communication Link (GGCL), was extended to Ukraine, Belarus, and Kazakhstan. Since 2013, the NRRC also maintains a communications link with Russia for the exchange of information about cybersecurity risks.

- In 2000 the US and Russia signed an agreement for the establishement of a Joint Data Exchange Center (JDEC) to share early warning information on missile and space launches to reduce the risk that a test launch could be misread as a missile attack. It's not clear whether this center has already been realized or not.

- In 2013, a direct secure voice line was set up between the US Cybersecurity Coordinator and the deputy secretary of the Russian Security Council in order to manage crisis situations arising from cybersecurity incidents.

- In 2015, the American and the Russian military created a back-channel after Russia entered Syria's multi-sided civil war. This de-confliction line consisted of a non-secure telephone line and a Google e-mail account, which proved useful in avoiding serious accidents.

- On March 1, 2022, a military de-confliction 'hotline' was established in order to prevent an accidental clash between Russia and the US during the Russian invasion of Ukraine. This link is basically an exchange of phone numbers between both sides for quick access. The US side will be run out of the US European Command's operations center in Stuttgart, Germany, while the Russian side is expected to be coordinated out of the Ministry of Defense in Moscow.


Besides these bilateral hotlines with Russia, the United States also has the following lower level communication links with other nations:

- There is a secure telephone line called Foreign Affairs Link (FAL) between the US Department of State and Russia (since 1999), Japan, Mexico, Germany and Israel.

- There is or was a Defense Telephone Link (DTL) between the US Department of Defense and Russia (since 1994), China (since 2008), Albania, Oman, Qatar, Latvia, Lithuania, Slovenia, Saudi Arabia, Ukraine, Bulgaria, Kuwait, Estonia, Slovakia, Kazakhstan, Macedonia, Bahrain, Israel (since 1996), United Arab Emirates, Poland, Romania, Czech Republic and Austria.

In March 2022, US defense secretary Llyod Austin and Joint Chiefs of Staff chairman Mark A. Milley tried to set up phone calls, most likely through the Defense Telephone Link (DTL), with their Russian counterparts, but the Russians declined to answer the calls.

- In September 2011, the United States proposed opening a direct military hotline with Iran to avoid a possible conflict erupting over the Iranian nuclear program. Tehran declined the offer.


UNITED STATES - UKRAINE

- Already before Russian armed forces invade Ukraine on February 24, 2022, the United States provided Ukrainian president Volodymyr Zelensky with a secure satellite phone that can put him into an encrypted call with US president Biden. On March 5, 2022, Zelensky used it for a 35-minute call with his American counterpart on what more the US could do to support Ukraine without entering into direct combat with Russian forces. A similar satellite phone was provided to Ukrainian foreign minister Dmytro Kuleba.

> See also: The phones of Ukrainian president Zelensky

UNITED STATES - UNITED KINGDOM

- During World War II, two decades before the hotline between Washington and Moscow was established, there was a direct secure telephone link between the Cabinet War Room bunker under Downing Street and the Pentagon with an extension to the White House. From 1943-1946 this link was secured by using the very first voice encryption machine, called SIGSALY.
In the 1950s and 1960s the Washington-London hotline was secured by the KY-9, probably succeeded by the KY-3 voice encryption devices. In the 1980s, the STU-I system was used, to be replaced by a small version of the IST red phone.

British prime minister Margaret Thatcher in her office at Nr. 10 Downing Street in 1987
At the far right we see the beige STU-I telephone for the hotline with the US
(photo: Tim Graham/Getty Images - click to enlarge)

UNITED STATES - GERMANY

- In 1962, a hotline was established between the White House and the German chancellor's office. Initially, this was non-secure, standard telephone line. In 1969 it was probably replaced by a secure teletype link and since the late 1970s it consisted of secure STU-I telephone sets. Somewhere in the 1990s these were replaced by a small version of the IST red phone.

> See: The hotline between Washington and
the former German capital Bonn

UNITED STATES - SPAIN

- The Spanish prime minister José Maria Aznar (1996-2004) was so often in contact with US president George W. Bush, that a special phone line was installed in his office in the Moncloa palace, exclusively for phone calls to the White House. One of those phone calls was just before the war in Iraq and both leaders also talked about developments in South America.*



UNITED STATES - CHINA

- In October 1997, US president Clinton and Chinese president Jiang Zemin agreed to "connect a presidential hotline to make it easier to confer at a moment's notice." On April 29, 1998 the United States and China signed an agreement to set up such a direct telephone link between both heads of state. However, this hotline was not used when in 2001 an American EP-3E electronic surveillance aircraft was forced to land on Hainan Island.

- In the Summer of 2021, the Biden administration examined the possibility of setting up an emergency hotline with the office of China's president Xi Jinping in order to avoid accidental escalation at a time of heightening bilateral tensions. However, it was believed that China views hotlines as tools to manipulate rather than to solve crises by de-escalating and communicating between forces like the US does. According to remarks by president Biden in July 2024, it seemed that the hotline between him and Xi had been established.

- On February 29, 2008, China and the United States had already agreed to set up a Defense Telephone Link (DTL) between the US Department of Defense and China’s Ministry of National Defense, which became operational in April 2008. Until 2011 this hotline was used only four times, but later it was used somewhat more often and in 2014, the US proposed to upgrade the DTL to video teleconference. In 2020, the DTL was used on a regular basis by various defense officials.


UNITED STATES - INDIA

- During a visit of US president Obama to India in January 2015, it was decided to set up a secure hotline between the White House and the Indian prime minister. The link became operational in August 2015 and was said to be established with the help of the US military.



RUSSIA - CHINA

- A hotline connection between Moscow and Bejing was used during the 1969 frontier confrontation between the two countries. The Chinese however refused the Russian peace attempts, and informed Moscow that the direct communications link "was no longer "advantageous" and normal diplomatic channels would suffice". After a reconciliation between the former enemies, the hotline between China and Russia was revived in 1996.* It's not clear whether this hotline is for record or voice communications.
- A telephone hotline between the defence ministries of Russia and China became operational on March 14, 2008.



RUSSIA - NORTH KOREA

- Apparently there was a facsimile-hotline between Moscow and Pyongyang, which was used in 1968, when North Korea captured the American spy ship USS Pueblo.*



RUSSIA - FRANCE

- Since 1966 there was a direct teletype connection between the French president and the Kremlin. In 1989 the teletype equipment was replaced by high speed facsimile units.*


RUSSIA - UNITED KINGDOM

- Since 1967 there was a direct teletype connection between the British prime minister and the Kremlin. In 1990 it was proposed to install a telephone line between London and Moscow, but British government officials considered it too costly to secure this line through encryption. It seems that this hotline was eventually upgraded with encryption in 2011.


RUSSIA - GERMANY

- In 1989 a facsimile connection was established between the West-German capital Bonn and Moscow.* In 1990 there was also a non-secure telephone line between both capitals.
- The Soviet Union also had a hotline with Erich Honecker as leader of the former East-German Republic (DDR). During a short period before East and West Germany were united in 1991, there was a telephone hotline between Honecker and the West-German Bundeskanzler Helmut Kohl.*



ISRAEL - EGYPT

- In 2009 Israeli prime minister Ehud Olmert and Egyptian president Hosni Mubarak agreed to pass on relevant intelligence information immediately using a hotline, primarily to combat smuggling from Sinai into the Gaza Strip.


ISRAEL - RUSSIA

- In 2015, Russian armed forces in Syria had set up a hotline with the Israeli military to avoid accidental clashes in the Syrian sky: "Mutual information-sharing on the actions of aircraft has been established through a hotline between the Russian aviation command center at the Hmeimim air base and a command post of the Israeli Air Force."



INDIA - PAKISTAN

- After the 1971 war between India and Pakistan, a secure communications link between the Prime Minister Secretariat in Islamabad and the Secretariat Building in New Delhi was established, but it was seldom used until the 1990s.
- In 2004, both countries agreed to set up an additional secure hotline between their foreign ministers, aimed at preventing nuclear risks.
- In 2011, India and Pakistan agreed to set up a 24/7 non-encrypted hotline between their interior ministers, that will facilitate real-time information sharing on terrorist threats.


INDIA - CHINA

- Since 2005 there's a non-encrypted hotline between the foreign ministers of India and China for building "mutual political trust".
- In 2009 both countries agreed to set up a direct, secure telephone link between the Chinese premier and Indian prime minister, which was meant as a confidence building measure and to maintain regular contacts at the highest level. The agreement for this hotline was signed in April 2010.


INDIA - RUSSIA

- There's also a non-encrypted hotline between Delhi and Moscow, which was established before 2009.



SOUTH KOREA - NORTH KOREA

- A first telephone hotline between North and South Korea became operational on September 22, 1971. Many low-level phone lines between both countries followed, until there were 33 lines through Pamnumjom and 15 lines outside that border town. A top-level telephone hotline between the presidents of North and South Korea was established on April 20, 2018, in preparation of a summit between both leaders.

> Read more: The hotlines between North and South Korea

A South Korean liaison officer speaks with his North Korean counterpart over the
inter-Korean communications channel at Panmunjom, January 3, 2018
(photo: Unification Ministry - click to enlarge)

CHINA - SOUTH KOREA

- In September 2012, China and South Korea agreed to set up a consular hotline between their defense ministries to protect rights of their citizens who are staying in the other country. In April 2013 both countries agreed to set up a second, 24-hour hotline to deal with the rising tension over North Korea.


CHINA - VIETNAM

- In June 2013, China and Vietnam agreed to set up a naval hotline between their defense departments, in order to keep a peaceful and secure maritime environment in the South China Sea, amid escalating maritime tensions over disputed South China Sea islands.


CHINA - PHILIPPINES

- In January 2023, an emergency telephone hotline was established after Philippine President Ferdinand Marcos Jr. met Chinese President Xi Jinping in Beijing. However, during a confrontation between Chinese and Philippine forces in August 2023, the Philippine government said it was unable to reach Chinese officials through this "maritime communication mechanism" for several hours.
- On July 2, 2024, both countries agreed to set up three new lines of communication to improve their handling of maritime disputes regarding the South China Sea:
1. for "representatives to be designated by their leaders";
2. for the respective foreign ministries at ministerial or vice-ministerial level;
3. for their respective coast guards.
It is not clear whether a direct line of communication between the Philippine and Chinese presidential offices was established as well.


In 2010, China and Japan agreed to establish a hotline between their political leaders, following a series of naval incidents, but the plan wasn't realized. Defence officials of the two countries also agreed in 2011 to set up a military-to-military hotline by the end of 2012, but the talks stalled due to heightened tensions over the territorial row. In February 2013, Japan again suggested to establish a China-Japan hotline, and reiterated this once again in January 2014.


In September 2016, China and the Southeast Asian countries decided to set up hotlines and adopt communications protocols to avoid potential naval clashes in the disputed waters of the South China Sea.


When more information about these hotlines becomes available, it will be added here. Some of the most notable bilateral hotlines will be discussed later on this weblog.



Links and Sources
- The Rand Blog: Another 'Hotline' with China Isn't the Answer, July 2022
- Politico: Pentagon wants Moscow back channels to prevent nuclear escalation, February 2022
- National Communications System, Forty Years of Service to the Nation: 1963-2003, 2003
- Haraldur Þór Egilsson, The Origins, Use and Development of Hot Line Diplomacy, Institute Clingendael, 2003
- US Department of State, Bureau of Information Resource Management (IRM), 2011