"T-Marker" is a Russian military commandment network serving the Western Military District. It broadcasts on 4325 kHz round the clock.

While no other traffic is being sent, the station emits its signature channel marker, which consists of intermittent tone dashes akin to the Morse code letter "T". The traffic consists mainly of "Monolith" format messages addressed to РХПВ (RHPW).

The network had previously used 4524 kHz, where the channel marker was first heard in July 2015. It disappeared later that year, only to return on the same frequency nearly two years later, on April 11, 2017. On April 4, 2018, the frequency was changed to 4182 kHz. Since then, it has temporarily moved to different frequencies, only to return to 4182 kHz:

• From July 26 to 30, 2018, it transmitted on 4593 kHz.
• From August 30 to September 12, 2018, it transmitted on 4593 kHz again.
• From October 27 to 29, 2018, it transmitted on 4223 kHz.
• From December 1 to 4, 2018, it transmitted on 4352 kHz.
• From December 19 to 21, 2018, it transmitted on 4280 kHz.
• From January 25 to 29, 2019, it transmitted on 4182.5 kHz.
• During daytime on January 21, 2020, it transmitted on 5070 kHz.

At 27th February, 2024, T-Marker dissapeared on 4182 kHz and didn't return before 9th April, 2024. It appeared on 4325 kHz USB with its marker, but at 22nd April, 2024, marker was changed to a longer one. At 16th June, 2024, right before T Marker's first message in 5 years, they were doing a lot of test counts and transmitter checks. After 1 day, at 17th June, 2024, the first message has been transmitted at 18:52 UTC.