Matt:

The hospital was Mt. Sinai in Manhattan. It has one main BIG building, taking up a half city block, with a height of 27 floors above grade, and three levels below grade. The other buildings are older and generally are 6 to 10 stories, but there are many of them.

The big building was cabled by electrical contractors, under the supervision of our lead man, who had designed the entire telephone layout. He was the lead man for many years and set the rules.

Every floor was wired identically. The layout of every main room and all of the satellite closets on every floor was uniform, with only minor differences due to the type of activity that took place on the floor.

On each floor, there was a main tel closet and three satellite closets. The main closet served as a fourth satellite, as well as its function as an equipment room. All telephone cables ran home to the 4 satellites, and were headed up on 66M-50 blocks.

The main room on each floor (the rooms were in the same "stack", so all cabling ran up a chase from the sub-basement to the top floor) was lined with chipboard on all walls, providing about 250 square feet of mounting area per main room, and the satellites had one 4 x 8 sheet of board each.

The main room on every floor had a floor-to-ceiling 23" equipment rack, which held anywhere from three to ten 584 panels. These are 1A2 common equipment that each hold 13, 400-type line cards. A large power unit or two was used to power the rack. Western Electric made a power cable that had 6 pairs of cotton-covered 18 gauge wire, covered in light olive gray (color suffix -49) plastic sheath. That was used to interconnect the panels.

The first panel in each rack had an interrupter, and subsequent panels had a plug-in relay unit in place of the interrupter, which was driven by the main interrupter, so that the flashing and winking lamps and the ringers of all lines on all phones would operate at the same cadence. If the number of lamps per circuit exceeded the design limit, solid-state lamp extenders were installed with a separate power unit dedicated for them.

The output cables of each panel were punched down on three 66B25 blocks each, giving 5 output pins for cross-connections. As an example, a room with eight panels would have 24 66B25 blocks just for the source of the features for that floor. The cross-connections sent the "features" to 66M-50 blocks which were the "source" end of individual 25-pair cables, each going to an individual 6- or 10-button phone. In the event that more than 5 phones needed the same features, we used "multiple" blocks, which could be wired using the loop-through method, providing as many multiples as needed, either in the main room, or at the other 3 satellite closets at the other quadrants of each floor. If more feature outputs were needed, more multiple blocks were added. There were NO bridging clips allowed, unless they were used for temporary service, while multiples were being installed.

Intercoms were the Teltone R-10 and R-19 units, each of which had its own 25-pair cable feed to a modified 66B-50 block.

A common audible lead from each 400D KTU fed a wall of diode matrix blocks. Strict physical layout rules and cross-connection color codes ensured that a repairman could walk into any room and find what he was looking for immediately. CA leads were red. Ground was black, fed from a large multiple 66 block. Every satellite had a ground multiple block, so that lamp grounds could be kept to a minimum resistance. Green was used to connect from the matrix blocks to telephone ringer leads. Brown was used for AC supply to buzzers, and white was the switched ground from manual signal buttons.

House cable pairs were home run from the MDF in the switch room, with enough pairs (generally 100 or more) to each floor. In the event that features from one floor needed to be assigned to telephones on other floors, they were never run floor-to-floor; they were run, via house pairs, to the MDF, cross-connected, and then run back up to the other floor via the house pairs for that floor. There were no inter-floor pairs installed, or allowed. There were about 4,000 house pairs just for the main building. The switch room housed the 701 PBX of 6,000 extensions and the 100-foot long MDF. The battery room was on another, lower, floor. The main room was approximately 120 feet by 60 feet.

Every main and satellite closet used the appropriate color-coded backboard system. Each main closet had a talk wire with auto ring-down circuit to the MDF key system.

House pairs were strictly documented (as were all feature assignments and lateral pairs). House pairs might carry a CO line, a PBX extension, or a feature from floor to floor. Of the seven people working full time at the location, only two were allowed to work on the frame, or make entries into the wire log, without supervision.

These rules may seem silly now, but the adherence to the rules was the only thing that kept the whole place from descending into chaos. Other installations of similar sized systems used many more persons-to-stations and had a much higher trouble rate per station. Our well-regulated system worked the best.

Arthur P. Bloom
"30 years of faithful service...15 years on hold"