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MDC for Repeater access
Posted: Fri Jul 04, 2003 3:47 pm
by walt10
Hi.
Is there a unit that can be used with a repeater controller to limit access by MDC?
Thanks Walt
Posted: Sat Jul 05, 2003 2:54 am
by The Pager Geek
Posted: Sat Jul 05, 2003 5:35 am
by Nand
The RICK manual on page 28 describes, in a rather confusing way, how to do this with GM300 or M200 type radios. It amounts to using the MDC call alert or emergency signal together with the alarm output on the radio to control the repeater. In this case the repeater receiver alarm output toggles a latch in the RICK that in turn controls the ignition control line of the repeater TX radio.
Nand.
Posted: Sat Jul 05, 2003 7:26 pm
by xmo
There are two basic ways that repeater access can be MDC controlled. One of these would be "control" in the sense of turning the system on or off or otherwise affecting the operation of the system by means of sending a predetermined MDC sequence. As Nand mentioned, the RICK provides one means of doing this.
The RICK uses the decode ability of the receiving radio it is connected to. Another concept would be to use an MDC decoder such as the MIDIAN. The output of the decoder could be interpreted by a simple computer - maybe even a BASIC Stamp - and thereby send commands to a repeater controller (a smart one like a CAT or LINK) This would be great for ham applications because different MDC codes could do a wide variety of repeater control functions.
The other context of MDC repeater access is the "official" Motorola context. Certain Motorola products like Spectra can be programmed for MDC RAT (RAT = Repeater Access Tone). This causes a specific repeater access MDC packet to be sent. This can be set up two ways. It can either be sent with a dedicated button press - or it can be sent on every transmission like a pre-ID - same concept - different opcode.
On the repeater end, Motorola has the SAM [Station Access Module] This device can be programmed in a variety of ways to activate the repeater. These are available as an option for Quantar and were available for MSF5000.
I am not aware of any third party equivalent of the SAM for generic application.