you'll want to know the framing and the coding.?
The framing is one of "d4" or "esf" for T1 or "cas" or "ccs" for E1
Note: "d4" could be referred to as "sf" or "superframe"
The coding is one of "ami" or "b8zs" for T1 or "ami" or "hdb3" for E1
E1's may have the additional keyword "crc4" to enable CRC4 checking
You'll want to know the signaling type - is it a PRI, is it E&M?
You'll want to know how many voice channels you've got. If it's PRI where your d-channel is.
If it's PRI, what type of PRI signaling is it.
If it's E&M, you'll want to know whether it's immediate, wink, or Feature Group D.
You'll want to know how many digits you get on dialed numbers.