Instruction manual

Hardware Overview
025-9416 21
Adjustment Pots
Three adjustment pots (item #14, Figure 3) on the peripheral board control audio levels to and
from the radio station card. They are accessed from the rear panel of the Model 640 chassis. The
RX adjustment controls the audio input level for the talkback feature. The TONE adjustment
controls the paging tone output level to the transmitter, while the VOICE pot controls the voice
audio output level to the transmitter.
Refer to Section 6 for details on adjustment procedures.
Jumper Settings
The jumpers on the Model 640 peripheral board control RF broadcast station interface para-
meters. Figure 5 shows the locations of each jumper on the peripheral processor circuit board.
JP10
JP8
a
b
JP7
JP1
a b
JP9
b
a
JP5
b
a
Front of
Model 640
Chassis
⇒
JP4
b
a
JP3
JP6
b
a
JP2
b
a
Figure 5. Peripheral Board Jumper Locations (Top View)
The jumpers on the peripheral motherboard are used as noted in Table 3.
Table 3. Table 3. Peripheral Mother Board Jumper Settings
Jumper Function Settings Default
JP1 Receive voice audio from Talkback pager
A - flat
B - de-emphasized
A
JP2 Transmit tone to transmitter
A - flat
B - pre-emphasized
A
JP3 Enables Talkback audio path or separate tone
output
A - tone output
B - Talkback
enabled (tx and rx audio)
B
JP4 COR (busy) polarity
A - active high
B - active low
B
JP5 Transmit voice audio to transmitter
A - flat
B - pre-emphasized
A
JP6 Terminal busy polarity
A - active high
B - active low
B
JP7
Factory test only (µProcessor U20 XIRQ)
IN
OUT
OUT