| 摘要 |
PURPOSE:To perform economically the test up to a digital terminal unit, by using a specific channel of the highway between the switch module of a digital exchange and a digital terminal shelf for the test. CONSTITUTION:A channel CH0 out of channels CH0-CH127 of a highway between a switch module SM and a terminal shelf DTSH is assigned for the test, and 8-bit folding test bit pattern ''10101010'' is transmitted. Digital terminal units DTU0-DTU3 separate 2-bit ''10'' respectively at timings (c)-(f) and apply separated ''10'' s to shift registers SR0-SR3 to delay them by components corresponding to 8 time slots. 2-bit ''10''s from registers SR0- SR3 are inserted to the same channel in data inserting partsI0-I3, and a multiplexer MPX transfers 2-bit ''10''s folded by units DTU0-DTU3 to the module SM as 8 bits on one channel. |
