Technical Bulletin 701-80
Issue 1, July 1958

HARD OF HEARING
TELEPHONE TYPE 80
(TRANSISTORIZED)

INSTALLATION AND ADJUSTMENTS —

1. DESCRIPTION
The type 80 Transistorized Telephone employs a transistor amplifier in
the receiving circuit for the purpose of aiding hard of hearing
subscribers. The Type 80 Transistorized Telephone is a self contained
desk set; no separate ringer box is necessary.
The set is equipped with a volume control and a 3-conductor line cord
which terminates in a small plastic 3-conductor connecting-block. The
connecting-block accepts wiring for either bridged or divided ringing.
No soldering is required. Telephone can be used on only 48-volt systems.

2. TRANSISTOR AMPLIFIER
The Type 80 Transistorized Telephone has a printed circuit amplifier
(page 28) ; no attempt should be made to repair it in the field. Remove
the printed wire board and replace it with a new one. (Order D-35290-A
as replacement board.)