Figure 2-1 Esd Caution Logo - Garmin GMA 240 Installation Manual

2.3.1 Internal Configuration Jumpers
The following internal configuration adjustments may be made by removing or replacing jumpers on the
PCB. The jumper positions are designed to accept a 0Ω resistor of 0603 size. Refer to
component location.
This service should only be performed by a qualified technician. Garmin is not responsible for damage
caused during adjustment of these internal configuration jumper settings. Refer to the GMA 240
Maintenance Manual for disassembly/reassembly instructions.
NOTE
The GMA 240 contains static sensitive components. Observe proper anti-static
procedures when performing any solder procedures on the unit.
Component Name
Alert Mutes
R0303
Music
COM1
R0304 Internal
Sidetone
COM2
R0305 Internal
Sidetone
TEL
R0308 Internal
Sidetone
TEL jack
R0315 detect
bypass
GMA 240 Installation Manual
Page 2-2

Figure 2-1 ESD Caution Logo

Table 2-1 Configuration Jumpers
Default
If this jumper is removed, music will not be interrupted by
Populated
alert audio. Default operation is recommended.
If a jumper is supplied in these positions, internal sidetone
Empty
will be heard during PTT to simulate received sidetone
from a radio that does not provide one during
transmission. This should only be used if a radio does not
Empty
perform this function already.
If this jumper is removed, intercom audio and intercom
sidetone will not be heard when the TEL button is
selected. Many phones supply sidetone when a call is in
Populated session. This causes a noticeable change in intercom
sound quality but it is usually not disruptive. Default
operation is recommended unless the effect of sidetone
from the telephone is disruptive to intercom operation.
If a jumper is supplied in this position, when TEL is
selected the audio panel will assume a telephone is in use
in the front jack regardless of phone detection. This
Empty
should be used only if the audio panel is not capable of
properly detecting the telephone that will be used in the
installation.
Appendix C
Description
190-00917-01
for
Rev. D