Mike's PBX Cookbook

M1 Network Configuration

Network
Group
0-7
Network
Shelf
0-1
Loops
0-255
INI
HEX
Code
Super Loops
0-252
PER
SIGS
0-15
3PE
Software
LD
IGS
1
Junctor
Jacks
J1-J22
IGS
0
Group 0 Shelf 0 0-15 9x 0, 4, 8, 12 0 (4x) 0G0 (EX) 2 (5x) J6 J1 0 (5x)
Shelf 1 16-31 Ax 16, 20, 24, 28 1 1G0 (Fx) 3 J17 J22 1
Group 1 Shelf 0 32-47 Bx 32, 36, 40, 44 2 0G1 6 J7 J2 4
Shelf 1 48-63 Cx 48, 52, 56, 60 3 1G1 7 J16 J21 5
Group 2 Shelf 0 64-79 Dx 64, 68, 72, 76 4 0G2 10 J8 J3 8
Shelf 1 80-95 19x 80, 84, 88, 92 5 1G2 11 J15 J20 9
Group 3 Shelf 0 96-111 1Ax 96, 100, 104, 108 6 0G3 14 J9 J4 12
Shelf 1 112-127 1Bx 112, 116, 120, 124 7 1G3 15 J14 J19 13
Group 4 Shelf 0 128-143 1Cx 128, 132, 136, 140 8 0G4 18 (6x) J10 J5 16 (6x)
Shelf 1 144-159 1Dx 144, 148, 152, 156 9 1G4 19 (6x) J13 J18 17 (6x)
Group 5 Shelf 0 160-175 13x 160, 164, 168, 172 10 0G5 - - - -
Shelf 1 176-191 14x 176, 180, 184, 188 11 1G5 - - - -
Group 6 Shelf 0 192-207 15x 192, 196, 200, 204 12 0G6 - - - -
Shelf 1 208-223 16x 208, 212, 216, 220 13 1G6 - - - -
Group 7 Shelf 0 224-239 17x 224, 228, 232, 236 14 0G7 - - - -
Shelf 1 240-255 18x 240, 244, 248, 252 15 1G7 - - - -

M1 System Sizes:

Some background info - from the days before IP!

The system uses timeslots to connect each party on an active call. These timeslots are present on Network Equipment components called Loops. Each Loop has 32 timeslots, and Super-loops have 128 timeslots. Loops and Super-loops are cards that sit in the Network Equipment shelves. 32 loops are called a group. The Option 81C is called a multi-group system because you can equip up to five Network groups. This was later expanded to 8 Network groups with a dual ring fiber optic network replacing the intergroup cards and intergroup module. This provided 7680 timeslots for 3840 simultaneous conversations. That's a pretty big PBX!

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