IBM System/370 145 Reference Summary page 142

Byte
Bit
0
1
2
0 3
GBO
4
5
6
7
0
1
2
1 3
GSP
4
5
6
7
0
1
2
2
3 GF
4
5
6
7
0
1
2
3
3
GTO
4
5
6
7
Ill
G1BUF (SX1Only)20,28,30 & 38
}
Fwd= BO
GC611
Bkwd = B3
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Spare
Chain Data
~
GB712
Command Chain
Sup Length Ind
Skip
Allow Halt
} GB412
Input Fwd
Input Bkwd
Output
Operational Out
GB313
Select Out
GB213
Address Out GB312
Command Out
GB312
Service Out
GB113
Data Out
GB113
Suppress Out
GB212
Spare
Selector Channel Logics
GA Pages Common to All Channels
GB and GC =Channel 1
GF and GG = Channel 2
GK and GL =Channel 3
GP and GO = Channel 4
11.18