Interface standards
Interfaces for connecting extensions to a PBX include:POTS (Plain Old Telephone System) - the common two-wire interface used in most homes. This is cheap and effective, and allows almost any standard phone to be used as an extension.
proprietary - the manufacturer has defined a protocol. One can only connect the manufacturer's sets to their PBX, but the benefit is more visible information displayed and/or specific function buttons.
DECT - a standard for connecting cordless phones.
Internet Protocol - For example, H.323 and SIP.
Interfaces for connecting PBXs to each other include:
proprietary protocols - if equipment from several manufacturers is on site, the use of a standard protocol is required.
QSIG - for connecting PBXs to each other, usually runs over T1 (T-carrier) or E1 (E-carrier) physical circuits.
DPNSS - for connecting PBXs to trunk lines. Standardised by British Telecom, this usually runs over E1 (E-carrier) physical circuits.
Internet Protocol - H.323, SIP and IAX protocols are IP based solutions which can handle voice and multimedia (e.g. video) calls.
Interfaces for connecting PBXs to trunk lines include:
standard POTS (Plain Old Telephone System) lines - the common two-wire interface used in most domestic homes. This is adequate only for smaller systems, and can suffer from not being able to detect incoming calls when trying to make an outbound call.
ISDN - the most common digital standard for fixed telephony devices. This can be supplied in either Basic (2 circuit capacity) or Primary (24 or 30 circuit capacity) versions. Most medium to large companies would use Primary ISDN circuits carried on T1 or E1 physical connections.
RBS - (Robbed bit signaling) - delivers 24 digital circuits over a four-wire (T1) interface.
Internet Protocol - H.323, SIP, MGCP, and Inter-Asterisk eXchange protocols operate over IP and are supported by some network providers.
Interfaces for collecting data from the PBX:
Serial interface - historically used to print every call record to a serial printer. Now an application connects via serial cable to this port.
Network Port (Listen mode) - where an external application connects to the TCP or UDP port. The PBX then starts streaming information down to the application.
Network Port (Server mode) - The PBX connects to another application or buffer.
File - The PBX generates a file containing the call records from the PBX.
The call records from the PBX are called SMDR, CDR, or CIL.
posted by Jack @ 9:26 AM
