March 2000 © TOSHIBA TEC
7-79
DP120F/DP125F Circuit Description
4.1 Line Path Switching Control Circuit
US/CA/TW models
The line path switching control circuit consists of the CML relay (RLY2) and analog switch
(IC51) on the NCU PBA, the I/OP-1 GA (IC7) on the Main PBA, and other peripheral devices.
The CML relay is switched according to the CML1 signal output from the I/OP-1 GA on the Main
PBA. When the CML1 signal goes HIGH, Q51 turns on to turn on the CML relay.
The analog switch is switched according to the CML1 signal and ATT3DB1 signal. When the
CML1 signal or ATT3DB1 signal goes HIGH, the analog switch turns on.
Turning on the CML relay and analog switch allows the MODEM to be connected to the line.
Fig. 7-4-3
07-04-01
Signal Name
Type
Active
Description
Destination
CML1
O
H
Line 1 CML Relay Control Signal
RLY2, IC51
ATT3DB1
O
H
Line 1 Attenuator Control Signal
IC51
Summary of Contents for DP120F
Page 1: ...PLAINPAPERFACSIMILE File No 31200001 R0112216901 TTEC ...
Page 401: ...DP120F DP125F Circuit Description 7 92 March 2000 TOSHIBA TEC 07 05 00 Fig 7 5 1 ...
Page 656: ...DP120F DP125F Troubleshooting 11 44 March 2000 TOSHIBA TEC ...
Page 700: ...DP120F DP125F Appendix 12 2 March 2000 TOSHIBA TEC 1 2 Error Count List ...
Page 701: ...March 2000 TOSHIBA TEC 12 3 DP120F DP125F Appendix 1 3 Function List for Maintenance ...
Page 702: ...DP120F DP125F Appendix 12 4 March 2000 TOSHIBA TEC 1 4 Drum Unit ...
Page 703: ...March 2000 TOSHIBA TEC 12 5 DP120F DP125F Appendix 1 5 Memory Dump List ...
Page 706: ...SHUWA SHIBA PARK BLDG A 2 4 1 SHIBA KOEN MINATO KU TOKYO 105 8524 JAPAN ...