It initially provided no support for Automatic Number Identification and no itemised record of calls, instead requiring subscribers to obtain expensive fixed-rate lines which included some number of hours of inbound calling from a " band " of one or several U . S . states or Canadian provinces.
22.
The caller would dial the long-distance operator ( typically 112 in large Bell System cities of that era; " 0 " was for local assistance ) and provide the destination city name and called number as well as their own number for billing purposes ( there was no automatic number identification ).
23.
The wire line facilities along the highway was changed from ring-down services to multi-party lines off dial exchanges as the communities along the line received central office switches, most of which were Ericsson Rurax switches that during the late 1970s were modified to enable direct dialing of long distance calls, though without automatic number identification.
24.
If the PSAP receives calls from the telephone company on older analog trunks, they are usually traditional telephone lines, but are formatted to pass the calling party's number ( Automatic Number Identification, ANI ) . ( For historical reasons, the PSAP will refer to these as CAMA circuits even though Centralized Automatic Message Accounting ( CAMA ) is actually a reference to the call log .)
25.
Systems which identify the caller's name and address to emergency telephone numbers ( such as Enhanced 9-1-1 in North America ) may be unable to identify which of multiple parties on a shared line placed a distress call; this is aggravated by the use of old mechanical switching equipment for party lines as this obsolete apparatus consistently provides no caller ID and often also lacks automatic number identification capability.
