Setting Up Polite MDC1200 Signaling

MDC1200 is a very useful tool on commercial radios. It can be used to do lots of cool things outside of simple radio identification signaling. But not everyone has a MDC1200 capable/compatible radio. On many radios hearing the MDC1200 data burst can become quite annoying, especially during nets. In this article I will outline what settings I use to prevent the MDC1200 data burst from being heard on many radios. Keep in mind, every radio is different so it may not work on every radio, but from what I've heard, most people can't hear it when I use this setup.

For this exercise, I will be using MOTOTRBO CPS Version 16.

These control how the MDC1200 data burst gets sent over the radio.

Pretime (in milliseconds) controls how long to wait before it starts sending the data.
Pretime is a way to delay the data burst to give time for the repeater (if applicable) and receiving radio to notice theres a signal and unsquelch.

Preamble Bit Sync controls how much padding (empty data) there is before the actual data starts.
Preamble Bit Sync is a way for the receiving radio to understand and sync up with the MDC1200 data in harsher RF conditions.

In most cases, the radio infrastructure in use is good enough that Preamble Bit Sync is unnecessary. 

I set my Preamble to 0, indicating there will be no Sync Bits. (Like the 'MDC without Preamble' audio above.)
As for the Pretime, I have mine set to 250ms. The idea here is to give it enough delay that the repeater (if applicable) and receiving radio 'wake up' before it happens, but that they don't unmute until its over or mostly over.

Quiet MDC1200