Plantronics 1632 Manual page 25

'
·~'ii"
2.7.2.2 SPACE MIXER BALANCE. Repeat for space mixer. Monitor
space mixer output (TP6) and adjust
sx,
SY and
sz
pots.
2.7.3 Time Base Board
2.7.3.1 LOOP DELAY CLOCK. A jumper (eyelets A-C) on the time
base is used to disable the delay clock if no high level loop
keyers are installed. The jumper must be moved to eyelets A-B
to enable the delay clock if high level loop keyers are to be
used.
2.7.4 Computer Control
2.7.4.1 UNIT SELECT. There are four unit select jumper
positions on this board. A jumper must be installed in one of
these positions corresponding to the unit select address.
2.7.4.2 REMOTE INPUT THRESHOLD. A potentiometer located near
Zl is used to adjust the threshold of the input circuits. This
potentiometer should be adjusted so that the voltage appearing
at Zl pin 2 is at the midpoint of the input signal voltage
swing. This adjustment must be made with an oscilloscope or
high input impedance VTVM.
2.7.5 Power Supply Board
2.7.5.1 LOW LEVEL OUTPUT POLARITY. There are two sets of
jumpers wfiTCh may be used to select the low 1 evel output of
each driver to conform to either MIL-188 or RS-232 polarity.
The output swing may be increased from +6V to +12V by removing
one of the zener diodes between pin 2 and pin
6
of the output
drivers.
2-9