IBM 5280 Manual page 259

E
2
COMMUNICATIONS MAP
3SLSMANUAL ANSWER
PAGE 3 OF
6
012
- Keep the telephone off hook.
- Connect a jumper from A-D7B02 ,-
Data Terminal Ready' to A-D7D08
'GND' •
Is the associated telephone
disconnected from the line?
Y N
013
Measure
Detection
A-D8BlO
l' and
'Current
A-D8B13
'Current Detection 2'.
Is one of' these
approximately
-3
Vdc?
Y N
014
GO TO PAGE
6,
STEP 028,
ENTRY POINT B.
signals
015
Measure
R
el ay' .
A-DSB03 'Transfer
Is the signal approximately -2.7
Vdc?
Y N
016
4 4
F G
Defective 38LS line adapter
card (A-D7)(MIM S12).
MAP 301S-3
No more tone; silent telephone.
A-DSBlO 'Current Detection l'
A-DSBl3 'Current Detection
signal levels:
On: -3 Vdc
Off: +1 Vdc
and
2'
A-DSB03 'Transfer Relay' signal
levels:
On: -2.7 Vdc
Off: -4.5 Vdc
The 'Transfer Relay' should be on
when the machine is in data mode
and the telephone lifted.
ECS40874 PECS397S7
MAP 3018-3