| 摘要 |
PURPOSE:To offer a MODEM testing system effective for seeking a fault of a MODEM of half duplex communication which has used a two-wire communication circuit, by sending a test pattern request signal from a main MODEM, and generating and sending back a test pattern from a sub-MODEM, when it has received said signal. CONSTITUTION:A test pattern request signal 202 is generated by a test pattern request signal generating circuit 4, and this signal is modulated by a modulating circuit 7, and sent out to a two-wire communication circuit 15. After sending-out of the signal concerned has been completed, a main MODEM1 becomes a receivable state by a two-wire controlling circuit 9. On the other hand, a sub-MODEM 2 demodulates said test pattern request signal 202 from the main MODEM1, by a demodulating circuit 8, detects is by a test pattern request signal detecting circuit 11, generates a test pattern 204 (for instance, a false random signal of 511 bits) by a test pattern generating circuit 10, and said pattern is sent out to the two-wire communication circuit through a transmitting data switching circuit 6 and the modulating circuit 7, and sent back to the main MODEM1. |
