This attribute specifies the specific variant of the Euro ISDN (ETSI-
T) protocol. Supported variants are:
etsiGeneric - provides generic ETSI-T protocol. Only proxy of the
NETWORK side of the protocol is implemented,
austria - provides ETSI-T protocol variant as per the Austrian
national specification. Only the USER side of the protocol is
implemented,
germany - provides ETSI-T protocol variant as per the German
national specification. Only the USER side of the protocol is
implemented.