Nortel Networks i2022 Series - Manual (Page 7)

i 2022 ISDN Teleset
5
ISDN INTERFACES
A little background information sometimes helps. Your ISDN service comes to you over ordinary telephone line wiring.
That makes it less expensive and simple to install.
There are a number of interfaces defined in Basic Rate ISDN. The most common of these interfaces are designated U, S,
and T. The letters U, S and T do not mean anything, they are reference points.
Your service provider (telephone company) will normally provide a 2-wire connection, called a U Interface.
Most ISDN Telephone Equipment (TE) uses an S or T Interface. The S/T Interface is a 4-wire Interface. A Network
Termination device (NT1) is used to convert the U Interface from the service provider to an S/T Interface.
The i2022 is an S/T Interface Teleset and is available, optionally, as a U Interface Teleset.
Figure 1: Line and Power Jacks
LINE AND POWER CONNECTIONS – i2022 TELESET
i2022 Equipped with an S Interface Module
The i2022 Teleset, when equipped with an S Interface Module, must be connected to the line through an NT1 device.
The Teleset is powered over the phone line. This method conforms to a standard using one of two different powering
methods: PS1or PS2. The i2022 requires PS2 power.
Switch Settings:
Power Switch
There is a PS1/PS2 power switch is located on the top of the S Interface Module. The PS1/PS2 power switch must
remain in the PS2 position.
TR Switch
When the i2022 Teleset is connected to the NT1 it acts as Terminal Equipment (TE). Terminal Equipment is any
(ISDN) device that terminates directly on the ISDN line without an adaptor.
If your Teleset is the last, or only, piece of TE on the ISDN line, set the TR to ON, otherwise it is set to OFF. This is
determined by the local equipment provider’s policy. It is suggested that you check with the ISDN provider or your
system administrator. Most companies allow up to eight TE units in the loop.
NOTE: The S Interface Module must be removed from the Teleset to gain access to the switch. See “Assembling
the Teleset.”
NOTE: The i2022, when equipped with an S Interface Module, requires an external NT1. When the i2022 is
equipped with a U Interface Module, an external NT1 is not required.