AT&T System 85 manual 426

ISDN 8510T Voice/Data Terminal

Recommended power supplies are the MSP-1 (local) Power Supply and the 1145A Bulk Power Supply.

Terminating Resistors

The terminating resistor jumpers are located on the upper left side on the bottom of the terminal. Above the pins, on the plastic housing, you will see the label TERM RESISTOR and a diagram of the correct settings.

These jumpers enable (ON) or bypass (OFF) the terminating resistor. The set is shipped with the jumpers in the OFF position bypassing the terminating resistor. You must verify that the jumper settings are set correctly for your configuration.

Note: The terminating resistor jumpers must be set only by qualified service personnel.

The terminating resistor jumpers must be set to OFF when the set is in a point-to-point configuration and the terminating resistor is in the closet or a 440A4 is connected on the line. When set to OFF, each of the two terminating resistor jumpers covers the two top pins in each set. (The bottom pin in each set is left uncovered.)

The terminating resistor jumpers must be set to ON when the set is in a point-to-point configuration and the terminating resistor is not in the closet or a 440A4 is not connected to the line. When set to ON, each of the two terminating resistor jumpers covers the two lower pins in each set. (The top pin in each set is left uncovered.)

The terminating resistor jumpers must be set to OFF when the set is in a multipoint confi- guration and the terminating resistor is in the closet, a 440A4 is connected on the line, or the jumper is set to ON in one of the other sets on the line. When set to OFF, each of the two terminating resistor jumpers covers the two top pins in each set. (The bottom pin in each set is left uncovered.)

The terminating resistor jumpers must be set to ON when the set is in a multipoint confi- guration and the terminating resistor is not in the closet, a 440A4 is not connected on the line, or the jumper is not set to ON in any of the other sets on the line. When set to ON, each of the two terminating resistor jumpers covers the two lower pins in each set. (The top pin in each set is left uncovered.)

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