- 413 -
with 33 way connector, pegs 3, 5, 13.
Switching Logic Unit used on a digital switching system to
convert indeterminate fleeting pulses from push buttons
into long fixed pulses suitable for feeding a diode
matrix. Also controls push button lamps and other
functions. Related units include UN23/4, UN23/5, UN23/6,
UN23/7, UN23/8, UN20/15. First used with BH-WRT switching
system covered by CDR7l. 33 way ISEP connector, coding
positions 3, 5, 29. DD 1967/69. CANCELLED.
Lapsed Time Logic Unit used in video tape machines, 1l5V
mains drive, to produce 6V positive going pulses to drive
an electronic clock indicator. CH1/l2. DD 1969.
Lamp Drive Logic Unit used in EPlM/ll to provide current
for lamp illumination on receipt of signals from UN23/9.
Each of the 8 drivers included has a spare gate input for
mass inhibition of lamps for multiple control point
Printed board with 33 way ISEP plug, coding
7, 29. DD 1969/70. CANCELLED.
Delay Logic Unit used in EPlM/ll at the Broadcasting House
end of the London-Wrotham switching system. Printed board
Combiner Logic Unit enabling 2 UN20/l5 to operate in
parallel so that either can feed logic to UN23/5 without
mutual interference. Printed board with 25 way connector
to fit PN3A/2l. Coding 3, 15, 17. DD 1969/70.
Buffer Logic Unit required when more than
required in PA2M/9.
5 UNl/98 are
DD Spec 2.364.
Logic Data Coder Unit used in
signals and multiplex them into
Printed circuit board with 64 way
BAl/4 to encode 32 input
a single binary signal.
G06 connecto'. DD 1972.
Monitor Control Logic Unit used to act as an interface to
board with 33 way ISEP plug. DD 1971. OBSOLESCENT.
Clock Synchroniser Logic Unit used to examine a received
bitstream and local clock and produce control signals for
UN23/l9. Also performs framing pattern recognition and
data recovery. Printed circuit board with 33 way ISEP
plug. DD 1971. OBSOLESCENT.
Pulse Stretching Logic Unit used in a digital signalling
system at receiving end to extend the duration of the
reset pulse to a
Printed circuit board
with ISEP 25 way connector, coding 3, 15, 21. DD 1971.