Lincolnshire Heritage Telephone Exchange
Lincolnshire HeritageTelephone Exchange

LHTE: PABX 7 Notes

Early May 2016 I was contacted because a PABX 7 had become available for purchase.  Totally surprised by this as I had given up hope of ever finding one let alone complete one.  The PABX 7 has been on my wish list for a very long time and I can tell you that I had become very excited by this news and there was no hesitation with regard to the purchase of this PABX.
One of the key things that had attracted me to the PABX 7 was the switchboard, trim and neat, this is an eye catcher compared to the standard Post Office switchboards of the same time period.  At the age of seventeen I would often be found watching the operator at AEI Semiconductors Lincoln, who used this switchboard,
May 16th 2016:-  Monday morning and a drive over to see the PABX 7 in the West Midlands, I was not disappointed, though the outside of the units had faded with time and had a few scratches, the inside was pristine.  Three and a half hours later I completed the financial transaction, loaded the twelve connecting circuits (two motion selectors) into the car for safe transport, choose the switchboard from the three available and then drove home.  As soon as I got in I cleaned the switchboard inside and out, removing a mass of dust from the extension dial keys, which after cleaning with a damp cloth all worked fine.
You will note from the picture below that I choose a  switchboard with the wooden ends and black extension keys, although the 8 and 9 have been replaced with ivory keys.

May 23rd 2016:-  Cable for the PABX7 arrived today, so from the exchange PCP (Primary Cross-connection Point) I pulled a 15m length of 160pr cable through the roof space down into the PABX room.  I then set about terminating the first lot of 160 pairs in the PCP.  Going on to pull a 6mm cable from the Rectifier / Battery feed to the PABX room and terminating the supply in to a fuse box.  The 6mm cable will happily supply 5 amps, into the PABX room.  For interest sack I will mention that I use old Wylex boards with the 5 amp push to reset breakers, they work perfectly with my low voltage dc supply and are a lot easier than using wired or cartridge fuses, and more responsive.
May 26th 2016:-  Preparation of the site for the PABX7 has started today, cleaned out a massive amount of junk and tidied up the back end of the PABX room.  Allocated an eight foot square floor area for the two cabinets, which leaves enough room for the doors to be opened back and front. Also decided on the route for the switchboard cable, having already allowed enough pairs to take it to the PCP in the 160 pair from the PABX 7, another 40 pair cable is need from the PCP to the Switchboard.
May 31st 2016:-  Started to pull through a one hundred pair cable from the Primary Cross-connection Point to the office where the PABX 7 switchboard is sited.  The office end has been terminated on to two female RJ21’s for the switchboard and five ten pair Krone blocks for any other use.  I have yet to terminate the other end in the PCP.
June 4th 2016:-Terminated the 100 pair cable feeding the switchboard in the PCP, also managed to jumper the 75 wires needed for to switchboard to link the office cable with the PABX 7 cable.  So the only wiring left at this point is the jumpers for the exchange lines, jumpers for extensions and the termination of the 160 pair cable in the PABX 7 its self.
June 5th 2016:-  Jumpered some exchange lines through to the PABX 7 and a couple of extensions from the PABX 7 to the office.  Stripped some sheathing off the 160 pair at the PABX end, tied off the groups ready for connecting.
June 14th 2016:-  Well the day arrived, Shane and I set off to Halesowen to fetch the PABX.  Threats of thunderstorms on the way and dark skies overhed whilst we loaded the van, however the rain held of long enough.

Loaded, two cabinets and fifty plus relay sets.

At home we had the task of moving the cabinets some distance across gravel, so we laid plywood sheets allowing us to take advantage of the original casters still fitted to the cabinets.

Rod & Shane moving the second cabinet across the gravel

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