| ADPCM |
Adaptive Differential Pulse Code modulation. A technique used to transmit data with a rate of 32Kbps |
| ANSI |
American National Standards Institute |
| ASCII |
American Standard Code for Information Interchange |
| ATM |
Asynchronous Transfer mode. A technique used to transmit data in cells of 53 bytes |
| Auto answer |
A feature of modems to answer automatically in phone calls for data communication |
| Baud rate |
Modulating speed for analogue signals |
| BCD |
Binary coded decimal. Binary code for decimal digits 0 to 9. |
| Busy Tone |
A tone advising the caller that the telephone number is busy. |
| Call Waiting Tone |
A tone advising the user of the call waiting supplementary service who is engaged on a call that someone is attempting to call his number |
| Carrier |
Signal of a specific frequency that is modulated and carries information |
| CCIT |
International Telegraph and Telephone Consultative Committee. |
| Codec |
Coder decoder |
| Compression |
Data compression technique for faster transmission |
| Congestion Tone |
A tone advising the caller that the groups of lines or switching equipment necessary for the setting-up of the required call or for the use of a specific service are temporarily engaged. |
| CRC |
Cyclic Redundancy Check. Error control checking |
| Datagram |
Message routing method used in packet switching where every packet is transferred independently from the previous packet in the same message |
| Dial tone |
A tone advising that the exchange is ready to receive call information and inviting the user to start sending call information. |
| db |
Decibel. A measuring unit of the ratio of two quantities |
| DTE |
Data terminal equipment |
| FDM |
Frequency division multiplexing |
| FDX |
Full duplex. |
| ISO |
International Standard Organization. |
| ISDN |
Integrated Services Digital Networks. |
| LDM |
Limited distance modem. |
| Off-hook |
The status of the phone when we have lifted the handset. |
| On-hook |
The status of the handset when it is on the phone. |
| PABX |
Private Automatic Branch Exchange. |
| Pay Tone |
A tone advising users of a payphone that a payment is required. |
| PBX |
Private Branch Exchange. |
| PCM |
Pulse Code Modulation. |
| POTS |
Plain Old Telephone System. |
| PSTN |
Public Switched Telephone Network. |
| QAM |
Quadrature Amplitude modulation |
| Ringing tone |
A tone advising the caller that a connection has been made and that a calling signal is being applied to a telephone number or service point. |
| RTS |
Request to send |
| SNR |
Signal to noise ratio |
| Special Information Tone |
A tone advising the caller that the called number cannot be reached for reasons other than "subscriber busy" or "congestion".
The tone may also be used in conjunction with recorded announcements to signify that what the caller is about to hear is a recording. It should always be used to precede all call failure announcements. |
| TDM |
Time division multiplexing |
| URL |
Universal Resource locator |
