单项选择题
The maritime access code for the IOR is（）in INMARSAT-A Telex Service.
A.581 B.582 C.583 D.584
单项选择题 In Inmarsat-A, “Priority 3” means（）communication.
单项选择题 Who has permit the SES enter the system after successful commissioning?（）
单项选择题 After successful commissioning, the（）will permit the SES access to system.
