GEC No's 127 & 137
The "Residence" type of C.B. wall telephone for use on manually operated systems may be obtained in either of two forms. For service where the system may he considered permanent and no change in the type of switching equipment is contemplated, instrument No. 127 may he employed. If, however, there is any possibility of the manual exchange being replaced at a later date by automatic equipment, the use of instrument No. 137 is recommended. In the latter a dial aperture, covered by a neat dummy, is provided in the front of the case. By fitting a dial in place of this dummy the set is immediately converted into the automatic type (Cat No. 27).
In all respects other than the provision of conversion facilities, the two instruments listed below are identical. The apparatus employed is of the highest standard throughout, as demanded for public service, and includes a solid hack transmitter, "Bell" receiver, induction coil, condenser and standard 1000 ohm ringer. The transmitter is mounted on a short adjustable arm. Woodwork, including the dial dummy in the case of Instrument No. 137, is of polished walnut. In order to give easy access to the interior of the set for wiring and inspection, the front is hinged and secured by a small screw lock.
Taken from the GEC Telephones and Switchboards (Manual and Automatic) Catalogue No. 11 (Circa 1936)
Last revised: January 30, 2021