Garmin GSR 56 Installation Manual - Page 22

3.9 Troubleshooting Refer to the Table 3-3 to troubleshoot any faults Table 3-3. Troubleshooting Problem Action • Check power wiring and pin out. No communication with GSR 56 • Verify correct communication port setting on display/control device. No or low-quality signal • Ensure the Iridium antenna has an unobstructed view of satellite constellation. • Check the antenna cable and connectors. • Verify antenna ground plane is adequate. No audio output • Check wiring from GSR 56 to audio panel or GDL 59 • Verify subscription with Garmin Iridium Services • Verify subscription with Garmin Iridium Services Unable to make a phone call • Verify signal quality is adequate • Verify communication between GSR 56 and the display/control device 3.10 Continued Airworthiness Maintenance of the GSR 56 is "on condition" only. For regulatory periodic functional checks, refer to approved aircraft maintenance manuals or manual supplements for actual aircraft maintenance requirements. Page 3-6 Revision F GSR 56 Installation Manual 190-00836-00