Integrated Solutions Digital Network (ISDN) is a postpaid solution currently available for corporate and business users in major cities.

ISDN is the digitalization of the access line between the exchange and the customer's premises, with a powerful signaling system associated with it.

The ISDN digital access provides the users with the possibility of initializing end-to-end digital connections that can support Voice, Data and a variety of added solutions. TTCL supports Primary Rate Access (PRA) 30B+D which has 30 bearer channels with 64kb/s capacity each and the solution is intended for those who want to connect ISDN PABXs.

ISDN solution is a fraud free solution and hence guarantees user a secure communication. TTCL enterprise use with ISDN solutions will also be able to use ISDN VAS solutions such as;