You must add the network-clock-select e1 0/0/0 command to the config to ensure the DSP's use the clock reference that is derived from the E1 RX bit stream on the E1 interface. This is then used to drive the BRI ports. Without this command, the BRI's will use the internal oscillator and there will likely be clock slips on all of the interfaces, including the E1. This will break fax and modem operation. Do a show controllers e1 and you see clock slips being registered.
The other thing to watch out for is that when a port is under MGCP control, the DSP's are always connected to the actual voice port. These may add delay or degradation to fax/modem calls. If you change to H323 operation, the router is capable of performing a pure TDM connection between the B channels on the PRI and the BRI ports - once the call connects the DSP is removed from the signal path and the B channels are cross connected across the router's TDM backplane. Refer here for more background -
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...
If you have 2 ISR routers, one acting as Failover, do we need to have both the same number of SRST licenses on the 2 routers?
No. You will only need the SRST licenses on the primary router. Because this feature...