A duplexing communication system can be either half-duplex or full duplex. Their livery is identical to that of other Duplex units. They are technologically similar to TGV Duplex sets, but single deck. Recombinases are capable of pairing oligonucleotide primers with homologous sequence in duplex DNA. Fessenden would also use duplex and multiplex commutator methods. Communication "is" possible over a connection in spite of a duplex mismatch. It emulates full duplex communication over a half duplex communication link. This variant is restricted to a half duplex mode. Each daughter strand becomes part of a new DNA duplex. The Victorian duplex in which Cobb lived still stands. "L" of a circular DNA duplex is its relaxed state. Its structure is unknown, except that it is persistently duplex, and extremely dense. Taxi frequencies are generally licensed in duplex pairs. Together with the 122-mm gun A-19 it formed a so-called "corps duplex". Khan first performed in an advertisement called Asian Duplex City.