Data Line Troubles - AT&T Network Adapter 25 Installation And Maintenance Manual

MAINTENANCE
Table 4-F.
ACTIONS FOR CIRCUIT PACK OPTIONS
CIRCUIT
PACK
,
ZTN76
ZTN77
ZTN78
TN742
TN753
TN760B Tie Trunk
TN763
TN767
Note: TN747 same as ZTN76 and ZTN77. TN746B same as TN742.

Data Line Troubles

Symptoms:
Data terminals connected through the Data Line CP (TN726) are dead
or are not functioning properly.
Procedures:
1. Check that the RS-232C connector on the Asynchronous Data Unit
(ADU) is properly connected to the RS-232C connector on the data
terminal. Always tighten connector screws and fasteners.
2. Check the terminal ac power connection.
3. Make sure that the connection to the ADU is a 4-pair modular plug.
4. Check the ADU ac power connection (see Steps 5, 6, and 7). An ADU
connected to a port on the CPU/Memory CP must have a local ac power
source. Briefly disconnect the ADU's power cord.
5. If the ADU is not externally powered, check pin 20 (DTR signal on the
RS-232C connector) for presence of at least +7 volts relative to pin 7
(ground).
4-100
Applicable Actions for Circuit Pack Options
(See Circuit Pack Options—Table 4-E)
CP
TYPE 32 33 34 35 36 37 38
GS Board
LS Trunk
Tip/Ring Line
Analog Line
DID Trunk
Aux Trunk
DS1 Interface
ACTIONS