Batboard

My department is updating all our mobiles in the entire fleet of firetrucks. We are replacing all the maxtracs with cm300's. We are wanting to enable MDC in all the radios so that the radios will identify themselves to each other. I have a very limited knowledge of MDC and am looking for pointers on how to program them.

I have not programmed the CM series before, so I will be learning the whole thing from scratch.

We are wanting the radio to show the ID of the truck (unit number...i.e. 210)

Any help you guys can give will be appreciated.

Very easy. Create (or use) the default system 1. Make sure MDC is enable on each channel you want to use it on AND enable MDC PTT ID on that channel (mode). You can also chose to program the ID to transmit before, after, or before AND after voice. My preference is before so people have to wait for the sidetone to stop before speaking...cuts down on people from "front clipping" their voice.

You can use up to 4 digits, including letters A-F. Thats it.

Let me tweak PJ's response a bit:

Valid MDC IDs are hexadecimal numbers, in the range 0001h through DEEEh. The hex value F is not allowed as any digit in a user ID: it is a wildcard for commands sent by the console. (For instance, if the console sends a StatAlert to 21FFh, all units whose ID begins with 21 will be alerted.) The hex value E is not allowed as the first digit in a user ID: it is used to signify a group call via the "secondary" or "variable" ID that is permitted in some subscriber radios.

As a result, there are a total of 47,250 possible MDC user IDs. (15^3*14.) (This is out of a possible 65,536 four-digit hexadecimal numbers.) How the IDs show up on the console is a function of console design and programming: they could show up as hex numbers, as their decimal equivalent, or as programmed aliases. Ditto for how MDCs show up on subscriber equipment (if the equipment is capable of and programmed for "UserID").

Do a Google search for C Plus III, and you will come to the page of the Cimarron C Plus III MDC decoder/encoder. This is a particularly useful device, both for dispatch points and mobile command posts. In addition, Cimarron has a couple of .pdf download files that give all sorts of useful hints and tips regarding the design of MDC systems.

For what it is worth, here is a design that I use for municipal fire departments:

First Digit: User type: 1 = Command Staff; 2 = engine companies; 3 = ladder companies; 4 = rescue companies; 5 = other department resources; 6 = non-department resources allocated call signs on the department radio (e.g., building inspector).

Second Digit: Radio type: 1 = portable; 2 = mobile.

Third Digit: Company number.

Fourth Digit: Serial.

Thus 1101 is the Chief's portable. 3211 is Ladder 1's front mobile.

This system is designed so that a dispatcher (or other user with access to MDC decodes) can more or less figure out who is calling without a list or alias available.