Code identifying the type of communication channel being used.
Code
Description
AA
Circuit switching
A process that, on demand, connects two or more data terminal equipments and permits the exclusive use of a data circuit between them until the connection is released (ISO).
AB
SITA
Communications number assigned by Societe Internationale de Telecommunications Aeronautiques (SITA).
AC
ARINC
Communications number assigned by Aeronautical Radio Inc.
CA
Cable address
Self explanatory.
EI
EDI transmission
Number identifying the service and service user.
EM
Electronic mail
Creating/sending/receiving of unstructured free text messages or documents using computer network, a mini-computer or an attached modem and regular telephone line or other electronic transmission media.
EX
Extension
Telephone extension.
FT
File transfer access method
According to ISO.
FX
Telefax
Device used for transmitting and reproducing fixed graphic material (as printing) by means of signals over telephone lines or other electronic transmission media.
GM
GEIS (General Electric Information Service) mailbox
Self explanatory.