1. Channelized T1/E1, are trunks with channelized bandwidth, I mean, T1 is divided in 24 and E1 in to 32 Channels.
2. Whereas, Unchannelized is the raw bandwidth of T1/E1 i.e., 1.544Mbps/2.048Mbps.
3. “Analog Call”, is analog, may be ‘coz of it’s local loop is analog… Usually local loop is analog.. and we use a pair of wires (with RJ11 – Jack) to connect the telephone. Digital Calls we can call it as ISDN call, we’ve ISDN NTs on out home and we connect Digital phones.
4. Number of trunks depends on the capacity of the call center. i.e., the call volume it is going to handle.
5. u can go for ISDN PRI/ T1/E1/
6. E1/T1 are not same as PRI, PRI uses a different signalling compared with E1/T1. But the bandwidth and no. of channels are going to be the same.
7. yes, again channelized E1/T1 uses different signalling (CAS), where as ISDN uses CCS.