Nortel Networks i2021 Series - Manual (Page 12)

i2021 ISDN Teleset
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Fig. 3: NT1 Leads
PS1/PS2 Switch Settings
n If power is supplied on pins 7&8, set the PS1/PS2 switch to PS2.
n If power is supplied on pins 3&6, 4&5 only, set the PS1/PS2 switch to
PS1.
n If power is supplied on pins 3&6,4&5,7&8, set PS1/PS2switch to PS2.
n If your NT1 does not supply power, you must use an external 48-volt
DC power supply. Contact your service provider or system
administrator if an external power supply is required. Connect as
follows (Figure 4) and set the PS1/PS2 switch to PS2.
Fig. 4: Powering a Teleset (S/T) with an External Power Supply
Terminating Resistors
The i2021Teleset has built-in Terminating Resistors. The Terminating
Resistor switches are located on the bottom of the Teleset. When the
switches are in the On position, the Terminating Resistors are installed.
The value of the resistors is 100 Ohms.