>Bell Labs/Western Electric could never get common control to work for > >steppers
>
> Actually, Ma Bell did have a small-scale successful deployment of
> common control for SxS offices, known as the Director system.
>
> The 'Directorized' SxS systems were not that common, and of course
> they did not scale nearly as well as the 'real' common control
> switches, but they did exist and they did work quite well.
>
> 712-366 was an example of this, the Manawa office in Council Bluffs,
> Iowa, which was cut to a DMS-10 in 1984 or so.
>
> The 'director' equipment (IIRC) sat between the linefinder and
> first incoming selectors and recorded the dial pulses or DTMF
> tones (yes, 712-366 had Touch Tone on step) and then either drove
> the selectors for an intra-office call or handled the trunk
> selection and outpulsing for an inter-office call.
>
> This scheme reduced the number of selectors necessary for a full
> seven-digit numbering plan without the need for the messy
> digit-absorbing schemes.
>
> Good day JSW
>
>
Bell experimented with lots of things from WW II on. Here's a gas tube controlled line/link network for a #1 Crossbar:
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