GSM Network Interfaces In order to ensure that networks could be assembled from elements from different manufacturers, standard interfaces were defined. In this way it could be guaranteed that the way they communicated would be the same whatever manufacturer. This approach enabled a large number of equipment manufacturers to enter the market and grew the overall number of suppliers and level of competition. The interfaces varied dependent upon the connection, i.e. which network elements or entities were being connected. GSM network interfaces list A series of different interface definitions were written and each given names as seen below. Um interface T he "air" or radio interface standard that is used for exchanges between a mobile (ME) and a base station (BTS / BSC). For signalling, a modified version of the ISDN LAPD, known as LAPDm is used. Abis interface This is a BSS internal interface linking the BSC and a BTS, and it ha...