terminal adapter
A device that provides ISDN compatibility to non-ISDN devices. An asynchronous terminal adapter turns an asynchronous bit stream into ISDN and is treated by the PortMaster as if it were a modem. A synchronous terminal adapter takes a synchronous bit stream and turns it into ISDN, typically supports V.25bis dialing, and connects to a PortMaster synchronous port. Some terminal adapters can be configured for either synchronous or asynchronous operation.