Analog Quantar Linking Using Cisco E&M Cards


Many people are using Cisco routers for P25 linking via the serial WIC cards. If your router can deal with voice hardware, then it is possible to use E&M cards to link with other mixed mode Quantars or analog repeaters, using the same router.

This PDF from Cisco gives you an overview about the necessary hardware, in short you need a router that can accept voice hardware, then depending on the router either a voice network module or a DSP module and a VIC E&M card. Also make sure that the IOS feature set running on the router can do both voice (LMR) and STUN. We use 2600XM series, 2801 and 2811 for example. E&M Type II interface model is used in our case, if you look at the E&M cards RJ45,  pin 1 is  left and pin 8 right, the TX and RX Audio pins 6&3 and 5&4 are connected to the Quantars orange analog audio connector at the back. PTT  is connected to the 50 pin Telco connector, E&M pin 8 goes to 7 on the Telco and E&M pin 7 is connected to 11 (AUX 1) on the Telco. E&M 1&2 are not used, we use VAD Ciscos voice activity detection. On the Quantar we need to configure a wildcard, first define AUX 1 to be active low, and then set up a wildcard entry that keys from WL when AUX 1 is low (active). This is only to show what is needed to pass analog wire line audio to the transmitter, you can setup more wildcard tables so that analog and digital not interfere. A little bit creativity is needed here to find the best solution for your needs. If you are using a Astro-TAC 3000 for mixed mode linking, then you don’t need the PTT cable and wildcard entry, the station will be keyed via the V.24 interface, even for analog transmissions.

 

 

I assume that  your router has networking configured and you can reach the distant router. Firs add this voice class to the configuration:

voice class permanent 1
signal timing oos timeout disabled
signal keepalive disabled
signal sequence oos no-action

Then apply this connfiguration to each voice port:

voice-class permanent 1
auto-cut-through
operation 4-wire
type 2
signal lmr
bootup e-lead off
lmr e-lead voice
lmr duplex half
lmr led-on
input gain 3
output attenuation -3
no echo-cancel enable
no comfort-noise
timeouts call-disconnect 3
timeouts wait-release 3
connection trunk 100
description E/M Voice Port 0

The bootup e-lead off and lmr led-on will not work on the 2600XM series, leave it out, it will work just fine, the downside is that the repeater or transceiver will be keyed up during the routers boot period.

If you are using a comparator or voter that needs guard tones, then use lmr duplex full, input and output levels are exaples, you may have to adjust them to fit your needs. Next  create the necessary dial peers first on router 1:

dial-peer voice 100 voip
description -your description here-
destination-pattern 100
session target ipv4: R2 IP
codec g711ulaw
ip qos dscp 5 media
ip qos dscp 5 signaling
vad aggressive

dial-peer voice 101 pots
destination-pattern 101
port 1/0/0

And this needs to be configured on router 2:

dial-peer voice 101 voip
description -your description here-
destination-pattern 101
session target ipv4: R1 IP
codec g711ulaw
ip qos dscp 5 media
ip qos dscp 5 signaling
vad aggressive

dial-peer voice 100 pots
destination-pattern 100
port 1/0/0

You can see how the 100/101 interrelate on both routers, so if you use the second voice port, you can configure more dial peers using 102/103 and port 1/0/1 insted of 1/0/0. The destination-pattern numbers are not important you can use everything as long as you have a matching pair. This setup is a one to one thing, perfectly fine if you use is with a voter or if you only need one link to a distant location. It is also possible to use Multicast, this way you can have multiple destinations and also tie in Cisco phones or listen in via PC for example. I will add Multi cast info as soon as possible.

3 thoughts on “Analog Quantar Linking Using Cisco E&M Cards

  1. Be careful with older 2600 and original VIC-2E&M cards. While I have not verified this myself it was mentioned to me during some of my experimentation that when the router reboots the signal levels on the E&M leads will change. This can result in a station keying while the router reboots. If you have used a 2600 you know that is not a short period of time. The configuration above makes mention of “bootup e-lead off” which I believe (and I’m sure it’s the internet so someone will correct me) resolves this issue but only in the VIC2-2E&M cards in the 2800/3800 series routers.

  2. I just set up a system following your page and i cant get any audio to pass-through the quantar, the cisco side of it all works great. but no audio in the wireline out to the xmtr.

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