| Division | Description |
|---|---|
| HB-1 | Drawings and Specifications |
| HB-8 | Cabling |
| HB-9 | Wiring and Connecting |
| HB-18 | Power Installation |
| HB-19 | Power Machines and Apparatus |
| HB-30 | Erecting, Aligning, and Mounting |
| HB-40 | No. 1 and Tandem Crossbar Transition |
| HB-50 | Unknown (Common Systems?) |
| HB-59 | Common Systems Tests |
| HB-61 | Testing of No. 1 Crossbar Central Office Originating Equipment |
| HB-62 | Testing of No. 1 Crossbar Central Office Terminating Equipment |
| HB-269 | No. 3 Electronic Switching System Testing |
| HB-281 | DIMENSION 2000 and Custom PBX |
| HB-282 | DIMENSION PBX Installation and Test of Auxiliary Equipment, and Feature Tests |
