Garmin GMA 240 Installation Manual - Page 14

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 0 Ω resistor of 0603 size. Refer to Appendix C for 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. The GMA 240 contains static sensitive components. Observe proper anti-static procedures when performing any solder procedures on the unit. Component R0303 R0304 R0305 R0308 R0315 Name Alert Mutes Music COM1 Internal Sidetone COM2 Internal Sidetone TEL Internal Sidetone TEL jack detect bypass Default Populated Empty Empty Populated Empty Description If this jumper is removed, music will not be interrupted by alert audio. Default operation is recommended. If a jumper is supplied in these positions, internal sidetone 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 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 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 should be used only if the audio panel is not capable of properly detecting the telephone that will be used in the installation. Page 2-2 Rev. B GMA 240 Installation Manual 190-00917-01