As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SATCOM WILL MAKE CALLS AND RECEIVE CALLS, BUT WE CANNOT TRANSMIT FROM SATCOM 1 OR 2. WHEN WE TRANSMIT WE CAN HEAR A SIDE TONE. ACFT GROUNDED. ACCOMPLISHED ACARS INTERFACE TEST. LINK TEST SUCCESSFUL AND WEATHER REQUEST RETURNED. VOICE TEST PASSES FOR BOTH SAT 1 AND SAT 2. REF AMM 23-15-00-730-801.