Panel - Zero Operator Trunk
By Ken Martin, ; posted February 24, 2006; hits 1119
| Panel Zero Operator 'A' Board trunk. The words "To Dist" mean "To District Frame Multiple" via TDF. When caller dials "0" 'L' operates, lighting a lamp on the 'A' board and returning audible ring to the caller. It also indirectly operates the slow release 320 ohm relay creating a hold path for the trunk. If caller hangs up first Relay 'L' releases then after a short time the SR relay releasing the trunk. If Operator plugs into trunk relay 'CO4' operates extinguishing lamp, releasing relay 'L' and cutting operator thru to the caller. An additional hold path is now created for the slow release 320 ohm relay. At this point the Operator has control of the call. Another piece of history from 3-24-1972. |
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