link service
A transmission service is a telecommunications service that is limited to the low- layer, network-relevant transmission functions, i.e., the functions in the network area, transmission and switching.
A transmission service provides the user with only a certain transmission capacity. The type of use is left to the user. For these services, the responsibility for compatibility in the unregulated layers lies with the user.
In Euro- ISDN, the transmission services available in Germany are line switching at 64 kbit/s and 3.1 kHz for the a/b interface and data packet switching via the D channel and the B channel. Furthermore, telephone service from the analog telephone network with data transmission via modems, screen text and telecopying.