Install the ASL_1.01 image as that works fine with RTCMs. There are no menu settings for configuring a RTCM so you’ll edit the conf files with your favorite editor. Many folks like WinSCP for that task. All the config files are in /etc/asterisk
The basic idea is to add a node or use an existing node or your server with the following differences:
edit rpt.conf channel driver: rxchannel = voter/1999 ; Replace with your node
add a voter.conf:
[general]
port = 667
password = BLAH
utos = y
[1999] ;change to your node number
Site1 = password1,transmit
buflen = 250
Wire the RTCM to your repeater:
Connect the discriminator audio output to the DB9 pin 3
Connect the CTCSS detect to pin 4
Connect PTT to pin 7
Connect Mic audio to pin 2
And finally you will need to telnet to the RTCM and configure the settings. The manual shows how to do this but you may need help. Please come back with your questions.