Ps1/Ps2 Switch Settings; Terminating Resistors; Fig. 3: Nt1 Leads; Fig . 4: Powering A Teleset (S/T) With An External Power Supply - Nortel i2021 Series User Manual

PS1/PS2 Switch Settings

If power is supplied on pins 7&8, set the PS1/PS2 switch to PS2.
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If power is supplied on pins 3&6, 4&5 only, set the PS1/PS2 switch to
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PS1.
If power is supplied on pins 3&6,4&5,7&8, set PS1/PS2switch to PS2.
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If your NT1 does not supply power, you must use an external 48-volt
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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.
i2021 ISDN Teleset

Fig. 3: NT1 Leads

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