Thursday October 07, 2004

Jumper monkey Humphreys at BT...

In the 1980's I worked at BT as a telephone contruction engineer. I even remember the group I worked in, PE49. I worked from BT's Cambridge depot and also from Royston Herts. I think I learnt there a lot of the work ethics I hold in high regard now. I learnt how to make tea. I had to remember each individual mug for each engineer, about twenty. How much milk, how much sugar. I did the pastie run. I had to take the orders and run into the town and bring back whatever folks wanted from the bakers.

While I worked for BT it was privatised. I saw the second System X 'digital' exchange go live in Arrington Cambridgshire . I worked on the new TXE2 electronic exchange in Chrishall Herts. To turn an empty building into a telephone exchange for the local village was something I remember well.

We had to manhandle racks weighing up to a ton. I usually got to yank on the winch handle to haul the rack upstairs. I learnt the cable colour code , that I still remember today. Cables with up to two hundred strands when you cut them open blue and white the first pair, orange and white the second... All these cables were tied into trunks around the exchanges with wax covered string. They were works of art.

So what is this jumper monkey nonsense about ? Well in the exchanges I worked at and I bet it is still similar you had jumpers, twists of wire for example connecting exchange equipment together to the customers line. This was called the MDF . Jumpering was the act of putting these wires in place.

One of the older exchanges I worked on was one of these . You can see the old electromechanical switches These exchanges were designed by an undertaker Strowger who thought his local manual exchange operator was diverting some of his business to his rival. The story of that is here . The electromechanical exchanges were very noise have a listen here

Why did I think of all of this ? Well this week we have been patching up the second batch of new engineers to move into the building. About sixty cat5/rj45 fly leads have been put in. Everyone was saying how mind numbing it was. Well as a jumper monkey we put in sixteen hundred for Chrishall a similar number of Arrington. Imagine the number in an exchange in London serving thousands of customers. When you did the jumpering one end was 'live'. Only fifty volts DC but it spat at you as you stripped and secured the wires on the terminals. The ring pulse that went down the wire was the worst I think. You only came into contact with that when you fed a ringer supply to a new rack.