A NEW TWIST IN TELEPHONY (Oct, 1953)

A NEW TWIST IN TELEPHONY

For years the accepted way to connect wires to telephone apparatus was with solder. Now, Bell Laboratories engineers have discovered how to make connections faster and better—without solder.

Solder, they reasoned, wouldn’t be needed if wire and terminal could be kept tightly pressed together. But, for economy, this had to be done with the wire alone—without complicating screws and springs.

They found the answer in using a properly dimensioned terminal with sharp edges … whipping the wire around it under high tension. The terminal bites into the wire, locking it securely into position. Thereafter the squeezed edges maintain a contact pressure of at least 15,000 pounds per square inch—even under vibration that cracks soldered joints.

The new connections can be made in half the time —a big money-saver in the billion connections that Western Electric makes each year for the Bell System. It’s another example of the way Bell Telephone Laboratories works continually to keep costs low.

BELL TELEPHONE LABORATORIES IMPROVING TELEPHONE SERVICE FOR AMERICA PROVIDES CAREERS FOR CREATIVE MEN IN MECHANICAL ENGINEERING

4 comments
  1. DocScience says: October 30, 201211:31 am

    This technology made mini-computers possible in the 1970′s and 80′s.

  2. Stephen Edwards says: October 30, 20122:19 pm

    Never thought of wire-wrap as being a big technological innovation, and didn’t know it was out of Bell Labs, but perhaps this is the right way to think about it. It sure is convenient at times.

  3. Just Old Al says: October 31, 20122:44 am

    Think I still have the tools and gun for making those connections around the shop somewhere. They are VERY right – those were convenient to use, easy to train untrained personnel to make (note the insulated wrap at the bottom – that is part of the specification) and almost impossible to short in high density panels if done properly.

    Minicomputers used this technology as pointed out above (DEC and DG most notably) but even a lot of the early S-100 bus microcomputers and endless hordes of homebuilts did. Been through many, many miles of AWG30 insulated wire doing that, i have…

    Al

  4. Toronto says: October 31, 20126:14 pm

    Yep. Even minis that were built with PCBs had wire wrapped cross-overs (it’s hard to design a printed circuit with a lot of connections and zero crossovers – even with computer assistance. And then there were FCOs (Field Change Orders) that would “patch” a board by cutting the pcb traces with an Xacto knife and replacing them with wire-wrap.

    Considering the low gate density of chips of those days, the number of cross connects was HUGE. A typical 32 bit processor in the early 1980′s was 3-5 19″ boards, after all.

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