If a trunk misses a given number of these messages, TUD declares the trunk down. When a trunk comes back up, TUD recognizes that the trunk is up, declares the trunk up, and returns it to service. See also trunk . TUV German test agency that certifies products to European safety standards. The wires can be shielded or unshielded.
Twisted pair is common in telephony applications and is increasingly common in data networks.
See also STP and UTP . TWS Two-way simultaneous . Mode that allows a router configured as a primary SDLC station to achieve better utilization of a full-duplex serial line. When TWS is enabled in a multidrop environment, the router can poll a secondary station and receive data from that station while it sends data to or receives data from a different secondary station on the same serial line. See XStream .