call incoming on each line and latched and unlatched
indication of call on any line. Controlled by d.c. only,
hence eliminating speech through selector keys. Intended
for use with UN10/35. SCPD 1977.
External Line Telephone Unit for use in PA19/14.
call/answer key and external line switching buttons to five
local entensions and three distributions. Updated version
of UN10/20. Not interchangeable. SCP D 1977.
2-4 Wire Converter for control line telephones.
a smaller printed circuit board and with min or
modifications. SCPD 1977.
Ring Detector Telephone Unit.
Two identical circuits each
providing telephone ringing detection and thyristor latch.
Dual improved version of UN10/29. SCPD 1977.
Provides lamp and tone caller flashing facility for control
line telephones. UN10/30 with fewer outputs on a smaller
printed circuit board. SCPD 1977.
Voice frequency ringer telephone unit which may be preset
to receive one of four single tones from line and apply
17Hz ringing current to a local handset when the tone is
present. It will also send tone to line when it receives
17Hz ringing current from the local handset. External
ringing current and voice frequency oscillators are
required. Operates from a supply in the range 12 to 50
volts. Replaces UN10/13 on a BMM chassis. CH1/ 65A. DD
1977. DDMI 6.304(77).
Voice Frequency Ringer.
Similar to UN10/41
contains OS3/11 ringing current and voice frequency
oscillators. CH1/65A. DD 1977. DDMI 6.305(77).
telephone which may be
receive one of four single tones from line and a pply 17Hz
ringing current to a local handset when the tone is
present. It will also send one of four preset tones to
line when it receives 17Hz ringing current from the local
oscillators are provided, but external oscillators may be
used if desired. Power requirements l2V to 33V d.c. at
320mA maximum. PO Chassis type 62. Supersedes UN10/13.
DD 1977. DDMI 6.331(78).
UN100044 UN10/44 & 44A Telephone Ringing Detector Unit, to provide mains signal
lamp calling and bell muting, used in conjunction with P.O.
telephone. Basic version operates on 50V and "A" version
operates on 24V. Power requiremen ts 50V. Eddystone box
l2lmm x 95mm. Supersedes BX5/22. SCPD 1977.
detection. Provides switched loop output at ringing
cadence. Unit can provide bell mute where line is
terminated on Line jack unit. For use on New Plan wiring
only. Power requirements 24 V or 50 V. Chassis 85 mm x
145 mm (M.K. double wall box). Supersedes UN10/44B.
Comms. Dept. 1985.