The adapters are intended to be used for {HEAD ~ calls} coming into a PBX on a DID trunk or {TAIL ~ E&M tie line} 
The adapters are intended to be used for { HEAD ~ calls } coming into a PBX on a DID trunk or { TAIL ~ E&M tie line }
OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL