I think you have an RJ48 jack, not RJ45. For T1/HDSL it will be wired as an RJ48C (vs. RJ48S for DDS).
Pin 1 Ring1 (XMT to CPE) or/wh
Pin 2 Tip1 (XMT to CPE) wh/or
Pin 4 Ring (RCV from CPE) blu/wh
Pin 5 Tip (RCV from CPE) wh/blu
I know this conforms to some spec (since its the same for all the T1 jacks I've worked with), but I can't say for sure if its per TIA-568B. I got the jack pin-out from the CPE wiring diagram for a Westell DSAWM-204 type-200 T1/HDSL mounting (I'm quite familiar with their products...), and the wire color from a cheat sheet we had lying about (don't know if your connections will be the same).
Joe
