MultiMobile MT128ZLX User Guide Appendix F: ISDN Glossary
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Router
A device used to connect and forward information between two or more network segments. A router is like a bridge
except with more capabilities. A router will determine the best route for a packet to take to get from point to point.
RJ-11
A common telephone jack. It is a six conductor modular jack that is wired with 4 wires.
RJ-45
An 8-pin modular jack that is a little larger than an RJ-11 jack and is used in networks and ISDN connections.
Service Profile Indentifier (SPID)
A set of numbers assigned to your ISDN line. They are provided to the ISDN subscriber by the phone company.
SPIDS are a unique identifier for each ISDN line.
S/T-interface
The part of the ISDN line that connects to the phone or computer
Switch Type
The brand or manufacturer of the equipment/software that the telephone company uses to provide ISDN service to
you. There are just a few switch types in existence and generally only one switch type is used per country except in
the United States.
Twisted Pair
A telephone company term for telephone wiring. The name comes from the fact that each pair of wires in the cable
are twisted to reduce attenuation (or crosstalk) in the wiring.
Voice Encoding
The method of transforming the analog voice signal picked up by a telephone handset into a digital signal in Pulse
Code Modulation form based on sampling. A-Law and Mu-Law are the two types of voice encoding used for ISDN.
U-Interface
A 2-wire ISDN circuit that connects the ISDN line to the central office. The U-type interface is more common than
the S/T interface.