Motorola SABER RVN4002K - Manual (Page 90)

DOS Mute Timer
DOS (Data Operated Squelch) is the radio's ability to mute the audio while examining the MDC
data packet that precedes many transmissions. This eliminates the miscellaneous noise at the
beginning of an incoming transmission that would otherwise be heard.
When selecting this option, you will be prompted for a timer value between 100 and 1500
milliseconds, in 5 millisecond steps. Whenever an MDC data packet is detected by the radio, it
will use this timer value to determine how long to wait before unmuting the audio. The default is
95ms greater than the MDC pretime. This is the recommended value.
84 Appendix - 5. Options List and Definitions