| 摘要 |
<p>When a MODEM controller detects that the receiving level of probing signals or tone signals having a specific frequency in the phase 2 of a precommunication procedure is lower than a prescribed value, the controller lowers the transmission speed of a control channel to a lower speed of 1,200 bps. When the controller lowers the transmission speed, the controller sets the transmission speed to 1,200 bps by using a prescribed bit in an MPh signal in a communication control procedure and, at the same time, executes communication at the lowered transmission speed by setting such a condition that the communication with the communication equipment on the remote side at a different transmission speed is not permitted by using another bit of the MPh signal and informing the communication equipment on the remote side of the set condition.</p> |
