APPENDIX 6
Glossary of Terms (continued)
Digital PSTN Digital Public Switched Telephone Network.
The digital national telephone system. Service is available to customers on
twisted-pair wires that may carry a DC supply provided from the network
telephone exchange, on optical fibre or other digital transmission medium.
The digital service may be in ISDN format or another digital format.
DTMF Dual Tone Multi Frequency
The series of tones used by telephones to send dialling information to an
analogue PSTN exchange. These tones are also used by the DTMF Fast
Format and Contact ID alarms reporting protocols.
DTMF Fast Format Alarms Reporting Protocol
A protocol that is a sequence of analogue tones (push-button telephone
tones) used to send via telephone lines a transmission to receiving equip-
ment at an ARC, and to receive checking and acknowledgement replies
from that receiving equipment. 8 or 16 channel DTMF Fast Format protocol
is commonly used in burglar or intruder alarm equipment.
DualCom96 Alarms Reporting Protocol
This protocol is used by DualCom GPRS to send transmissions to receiving
equipment at an ARC, and to receive checking and acknowledgement re-
plies from that receiving equipment. This is a Modem type protocol
Earth Loop Calling
An older type of analogue PSTN or analogue PABX extention line. Normally
provided with no DC voltage present on the line. Requires the line to be
connected to earth to obtain a ‘dial tone’. DualCom can not be used with
this type of telephone line.
GPRS General Packet Radio Service
Digital telephone service particularly (but not exclusively) for users that may
be mobile for carrying digital data (typically internet) where the path from the
user is by a radio link to one (or more) fixed sites.
Hybrid Line
A line that carries digital data and analogue signals simultaneously. Most
commonly this is an ADSL digital service and an analogue telephone serv-
ice on one line from a Service Provider to a subscriber.
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