WE 543 DBC - Converted in 1963
WE 543 DBMW - without Bell System markings. 8-78.
NOS in box.
|Western Electric 543 -- 4-button,
line, specific to a 761A PBX, designed for the small hotel/motel
used in the guest rooms. (I don't ever remember staying in
hotel that used them!)
Control buttons, exclusion key and "A-leads" (control leads) tell the switching equipment what kind of line to connect to the set (switching done within the PBX). Buttons marked:
"Message waiting" (the front desk could illuminate it to alert you to a message),
"Desk" (connected you to the front desk),
"Local" (connected you to a CO trunk for a local call), and
"Long distance" (gave you a direct path to a toll operator).
The last three buttons are momentary contact.
These button features relieved the attendant of having to route much of the guest traffic.
Outwardly, these sets look like a 544 or 545 set but have fewer line cord conductors (12).
543DB – 641A line key, C4B ringer
543DBC – 588B line key, C4A ringer – field/distributor converted from 544BB or 545BB.
The later models with square line keys are the only four button keysets I've seen with square keys.
The 761A PBX introduced several new features to help the motel owner-operator, including "Remote Answer." The attendant could answer incoming calls from any room telephone when away from the main console. Incoming calls to a guest room could then be "extended" to the desired room.
Field trials were held in Arizona, Florida and Tennessee in 1963, with installations beginning in 1964.
"761A PBX," Bell Laboratories Record, July-August 1964, p.247 (in the TCI Library).
"Phone Service for Small Motels," Singing Wires (TCI), September 2016, p. 1.