As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
TRIED TO CONTACT MEDLINK ON SAT2 WAS ABLE TO TALK FOR 2 MINUTES AND THEN THE LINE WENT BLANK. UNABLE TO DISCONNECT CALL (MCDU MENU INDICATED "CALL ANSWERED" WITH NO DISCONNECT PROMPT. GROUNDED - YES. PERFORMED SATCOM COMMUNICATION SYSTEM TEST GOOD REF B737-900 AMM 23-15-00-730-801. MEDLINK COMMUNICATION TEST GOOD AMM 23-52-00.