GLOSSARY
DTMF
Short for Dual Tone Multi-Frequency, the system used by touch-tone telephones. DTMF assigns a specific frequency (consisting of two separate tones) to each key so that it can easily be identified by a microprocessor.
E1
E1 is the European format for digital transmission. It carries signals at 2 Mbps (32 channels at 64Kbps, with 2 channels reserved for signalling and controlling).
ISDN
Abbreviation of integrated services digital network, an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires. ISDN supports data transfer rates of 64 Kbps (64,000 bits per second).
LINECARD
An electronic circuit on a circuit board that interfaces between subscribers to a telecommunications network and the rest of the network. A line card have commonly been used to interface the twisted pair cable of a POTS local loop with the public switched telephone network (PSTN). Line cards used on the PSTN may have many functions, including:
conversion of voice transmissions from analogue to digital or vice versa
detection of off-the-hook receivers
MULTIPLEXING
A process where multiple analogue message signals or digital data streams are combined into one signal over a shared medium. The aim is to share an expensive resource.
PCM
Short for pulse code modulation, a sampling technique for digitizing analogue signals, especially audio signals. PCM samples the signal 8000 times a second; each sample is represented by 8 bits for a total of 64 Kbps.
PCB
A thin plate on which circuit design is printed so that chips and other electronic components can be placed
T1
T1 carries signals at 1.544 Mbps (24 channels at 64Kbps). E1 and T1 lines may be interconnected for international use.
DTMF
Short for Dual Tone Multi-Frequency, the system used by touch-tone telephones. DTMF assigns a specific frequency (consisting of two separate tones) to each key so that it can easily be identified by a microprocessor.
E1
E1 is the European format for digital transmission. It carries signals at 2 Mbps (32 channels at 64Kbps, with 2 channels reserved for signalling and controlling).
ISDN
Abbreviation of integrated services digital network, an international communications standard for sending voice, video, and data over digital telephone lines or normal telephone wires. ISDN supports data transfer rates of 64 Kbps (64,000 bits per second).
LINECARD
An electronic circuit on a circuit board that interfaces between subscribers to a telecommunications network and the rest of the network. A line card have commonly been used to interface the twisted pair cable of a POTS local loop with the public switched telephone network (PSTN). Line cards used on the PSTN may have many functions, including:
conversion of voice transmissions from analogue to digital or vice versa
detection of off-the-hook receivers
MULTIPLEXING
A process where multiple analogue message signals or digital data streams are combined into one signal over a shared medium. The aim is to share an expensive resource.
PCM
Short for pulse code modulation, a sampling technique for digitizing analogue signals, especially audio signals. PCM samples the signal 8000 times a second; each sample is represented by 8 bits for a total of 64 Kbps.
PCB
A thin plate on which circuit design is printed so that chips and other electronic components can be placed
T1
T1 carries signals at 1.544 Mbps (24 channels at 64Kbps). E1 and T1 lines may be interconnected for international use.
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