Checking The Installation And Isolating Failures
Check the telephone installation for proper operation by performing the following voltage measurements.
Voltage Check
Make the following voltage measurements at the station connector blocks under the following conditions:
•
Common equipment connected to station connector blocks.
•
Stations wired and wiring punched down on blocks.
•
Bridging clips installed
•
AC power connected to the common equipment
Measure the DC voltage across the Tip and Ring leads for each installed telephone with a DC voltmeter. Then,
call the industry-standard telephone to stimulate the ring generator assembly and measure the AC ringing voltage
across the Tip and Ring leads for each installed telephone with an AC voltmeter.
The measured voltages must be within the limits shown in the chart below. If your measured readings are
different from these charted values, it could indicate a possible wiring error or a station or common equipment
problem.
66M-xx Connector
Meter Lead Polarity
Measured DC Volts
Measured AC Ring
Voltage
Tip Lead
– 36
±
3 VDC
60
±
5 VAC
Ring Lead
–
IMI89–268
Installing The IST Station Board
Charlottesville, Virginia 22901-2829
R
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