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Adjustment Procedures
88
025-9416
TRUNK C
TRUNK
D
LINE ANS ACT
LINE ANS ACT ANA PTT DIG PTT BUSY
GROUND
TRUNK D
TRUNK C
MODEL 640 DAPT XTRA
AGC KILL
FROM TEL
BAL R
BAL C
AGC KILL
FROM TEL
BAL R
BAL C
A
B
Figure 51. Trunk Card Level Adjustments
q
8.
Set the meter range for 3-5 V
AC
.
q
9.
Connect a buttset or equivalent high impedance monitor to the appropriate trunk.
q
10.
Dial into the trunk (using any touch-tone phone) by way of the local telco CO.
q
11.
Verify that the line under test is the same line dialed by monitoring the line for voice
on the buttset. (Speak into the telephone and listen on the buttset.) If no audio is
heard, redial to access the correct trunk.
q
12.
Press and hold down one of the telephone’s touch-tone keys. (‘A’ transmits the
highest and lowest DTMF frequencies - 697 and 1633 Hz. If the phone does not have
an ‘A’ key, ‘3’ is the next widest tone pair - 697 and 1477 Hz.)
q
13.
Set the AGC KILL switch to the kill position (toward the rear of the chassis). The
figure above shows the location of the AGC KILL switch and the potentiometers. Do
NOT kill the gain control until ready to make actual adjustments, as DTMF decoding
usually does not work with this setting.
q
14.
Adjust the FROM TEL pot until the voltmeter reads 3.0 V
RMS
±
0.25 V
RMS
.
q
15.
Set the AGC KILL switch back to the normal position (toward the front of the
chassis).
q
16.
Verify that the FROM TEL DTMF level is
≈
-8 dB (435 mV
rms
) with the gain control
active.
Note:
This tunes the knee of the AGC circuit for optimum operation.
q
17.
Hang up the telephone and terminate the call.
The FROM TEL adjustment is complete.
Summary of Contents for 640 DAPT XTRA
Page 2: ......
Page 6: ...Statements vi 025 9416...
Page 20: ...Introduction 8 025 9416...
Page 26: ...Specifications 14 025 9416...
Page 96: ...Installation 84 025 9416...
Page 126: ...Optional Equipment Installation 114 025 9416...
Page 134: ...Voice Prompts 122 025 9416...
Page 174: ...Parts Lists and Schematics 162 025 9416 Schematic...
Page 175: ...Parts Lists and Schematics 025 9416 163...
Page 176: ...Parts Lists and Schematics 164 025 9416...
Page 177: ...Parts Lists and Schematics 025 9416 165...
Page 178: ...Parts Lists and Schematics 166 025 9416...
Page 179: ...Parts Lists and Schematics 025 9416 167...
Page 180: ...Parts Lists and Schematics 168 025 9416...
Page 181: ...Parts Lists and Schematics 025 9416 169...
Page 182: ...Parts Lists and Schematics 170 025 9416 Silkscreen...
Page 185: ...Parts Lists and Schematics 025 9416 173 Schematic...
Page 186: ...Parts Lists and Schematics 174 025 9416...
Page 187: ...Parts Lists and Schematics 025 9416 175...
Page 188: ...Parts Lists and Schematics 176 025 9416...
Page 189: ...Parts Lists and Schematics 025 9416 177...
Page 190: ...Parts Lists and Schematics 178 025 9416 Silkscreen...
Page 193: ...Parts Lists and Schematics 025 9416 181 Schematic...
Page 194: ...Parts Lists and Schematics 182 025 9416...
Page 195: ...Parts Lists and Schematics 025 9416 183...
Page 196: ...Parts Lists and Schematics 184 025 9416 Silkscreen...
Page 198: ...Parts Lists and Schematics 186 025 9416 RAM Disk 702 9386B ROM Disk 702 9389B...
Page 199: ...Parts Lists and Schematics 025 9416 187 TNPP Interface 702 9362C 2...
Page 200: ...Parts Lists and Schematics 188 025 9416 Terminal Block Adapter 702 9470B...
Page 201: ...Parts Lists and Schematics 025 9416 189 CONFIGURATION DIAGRAMS Dual Trunk Telco DID 024 0076A...
Page 202: ...Parts Lists and Schematics 190 025 9416 Dual Trunk Telco End to End 024 0077A...
Page 203: ...Parts Lists and Schematics 025 9416 191 Dual Trunk Telco E M 024 0078A...
Page 204: ...Parts Lists and Schematics 192 025 9416 Dual Trunk Telco Ground Start 024 0079A...
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