I have a PBX with an E1 link going to R1. R1 goes via ethernet to R2 which has an E1 going to the UK PSTN. (I haven't actually installed the routers yet).
1. What kind of E1 cards to I require? I've seen both balanced and unbalanced versions of NM-1CE1T1-PRI and NM-1CE1.
2. What config is required to activate the E1 cards?
3. What E1/voice specific config is required to carry calls from the PBX to the PSTN?
4. How does R2 know to use the different E1 channels? Is it by using multiple dial-peers?