AT&T System 25 - Manual (Page 277)

MAINTENANCE
Table 4-F. Applicable Actions for Circuit Pack Options
ACTIONS FOR CIRCUIT PACK OPTIONS
(See Circuit Pack Options—Table 4-E)
CIRCUIT CP ACTIONS
PACK TYPE 32 33 34 35 36 37 38
,
ZTN76 GS Board
● ● ● ●
ZTN77 LS Trunk ● ● ● ●
ZTN78 Tip/Ring Line
● ●
TN742 Analog Line ● ● ● ●
TN753 DID Trunk
● ● ● ●
TN760B Tie Trunk
● ● ●
● ●
TN763 Aux Trunk ● ●
TN767 DS1 Interface
● ● ●
●
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).
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