WHEN I WAS IN THE U.S. ARMY FROM 1966 THRU 1968, I WAS IN A UNIT KNOWN AS "EGSM" IN GERMANY. IT STOOD FOR "EQUIPMENT GENERAL SUPPORT MAINTENENCE", WHICH IS WHAT WE DID.
EGSM stands for Extended Global System for Mobile communication .
This is introduced to enhance the capacity of the network, i.e., to accomodate more number of mobile subscribers .