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