Registering voice-ports from a Cisco 881 SRST router to CME / UC500

The Cisco 881 router comes in an SRST flavor (C881SRST-K9) which includes 1 FXO and 4 FXS ports.  We recently ran into a problem at a customer’s new install where the service provider did not run new FXO lines in time for the installation.  So seeing that we had some FXS ports available, and being familiar with integrating the VG224 and VG204 to CME, I set out to see if the FXS ports in the 881 could be registered via SCCP to the CME across the WAN.  The answer is yes!

Here are the relevant parts of the config in the 881:

stcapp ccm-group 1
stcapp
!
interface FastEthernet0
ip address 192.168.2.1 255.255.255.0
!
voice-port 0
timeouts ringing infinity
caller-id enable
!
voice-port 1
timeouts ringing infinity
caller-id enable
!
sccp local FastEthernet0
sccp ccm 10.1.1.1 identifier 1 version 3.1
sccp
!
sccp ccm group 1
associate ccm 1 priority 1
!
dial-peer voice 100 pots
service stcapp
port 0
!
dial-peer voice 101 pots
service stcapp
port 1

And on the CME

interface Vlan100
ip address 10.1.1.1 255.255.255.0
!
ephone-dn 35
number 1234567
description Remote 881
!
ephone 1
device-security-mode none
description 881 FXS Port 0
mac-address 0000.1234.5678
max-calls-per-button 2
type anl
button 1:35
!

For me the ephone showed up automatically, but you might need to add it manually.  If that’s the case use the following command on the 881 to determine the mac address for port 0:  “show stcapp device voice-port 0”  In the output under the “Device Name” field the mac address will be the last 12 characters of the name.