E.F. Johnson Company 5100 Series, Service Manual

Page: 20 / 173

BATTERY, ACCESSORY, AND DISASSEMBLY INFORMATION
2-3
Figure 2-3 Accessory Installation
Latch
Install Lock
Screw Here
Accessory Connector
Hook
2.3 ACCESSORY INSTALLATION
To connect an accessory such as a speaker-
microphone to the transceiver, refer to Figure 2-3 and
proceed as follows:
1. Remove the dust cover over the accessory jack on
the side of the transceiver.
2. Insert the hook of the accessory connector into the
slot on the side of the transceiver.
3. Hold the latch open, press the connector against the
transceiver, and then release the latch to lock the
connector in place.
4. Install the included locking screw in the latch tab in
the location shown.
Option Select Lines
Opt Sel 1 (pin 1) and Opt Sel 2 (pin 5) of the
UDC (accessory) connector indicate to the control
logic when an accessory is connected and what acces-
sory is installed. These lines function as follows:
Opt Sel 1 and 2 High (3.3V) - This is the normal
operating condition in which no accessory is
connected. Both lines are pulled high (3.3V) by
internal pull-up resistors.
Opt Sel 1 Low - A speaker-microphone or some other
accessory is connected. Opt Sel 2 then functions as an
external PTT line (low = PTT), and the radio PTT
switch is also functional. The internal speaker and
microphone are disabled.
Opt Sel 1 High, Opt Sel 2 Low - The encryption
keyloader is connected.