Conventional DS1 service uses Channel Associated Signaling or CAS, that is how channelized service functions. Each channel has signaling bits that provide on-hook or off-hook indication and some do three-state signaling for its own channel. Whatever information is sent, is done on an individual channel basis. This type of DS1 service can be configured in several ways depending on customer equipment capability and purpose, ie: tie trunks, CO trunks, INWATS trunks, OUTWATS trunks, etc.
Now, I don't know what kind of service you receive on the DS1 you currently have from Sprint, but looking at the switch configuration should be telling. From my background, the only service offering that provided ANI (reference bluemr2 post above) was INWATS TOLL FREE in the format I mentioned in my posts above. There again, we keep beating the dead horse: ANI - CID. In addition unless your PBX equipment has software that will enable that type of format you WILL NEVER GET ANI!!!!!!!!
ANI IS NOT CID! ANI IS NOT CID! ANI IS NOT CID!
....JIM....