AT&T 6300 Service Manual page 260

DIAGNOSTICS
The parallelloopback jumper is a male 25-pin connector that fits
into the parallel port on the rear panel of the System Module. The
loopback jumper is wired as follows (Figure 4-2):
Pin 1 (-STROBE) to Pin 13 (SELECT)
Pin
2
(PTDO) to Pin 15 (-ERROR)
Pin 10 (-ACK) to Pin 16 (-INIT)
Pin 11 (BUSY) to Pin 18 (GND)
Pin 12 (PE) to Pin 14 (-AUTOFDX)
o
}
0 0 0 0 0 0 0 0
14 5 1 17 18 19 20 21 22 23 24 25
0 0 0 0 0 0 0
2 3 4 5 6 7 8 9 1 11 12 1
o
13
Figure 4-2. Parallel Loopback Jumper
4-68