Abstract: A ring network, which can reduce the amount of processing, deal with the occurrence of faults, and lighten the load on an operator, includes a plurality of transmission apparatuses each including a cross-connect function unit and a communication function unit for sending and receiving messages using the overhead of an SDH frame, and a master transmission apparatus to which a command is input for switching from a UPSR to BLSR mode including a path management database, a path decision unit, and an interchange decision unit. The master transmission apparatus to which the command is input collects and stores path setting information of all of the transmission apparatuses in the path management database and sequentially performs processing for deciding on and deleting a long path and processing for interchanging a path on a protection channel to an idle work channel by sending and receiving a message.

Abstract: A ring network, which can reduce the amount of processing, deal with the occurrence of faults, and lighten the load on an operator, comprised with a plurality of transmission apparatuses each including a cross-connect function unit and a communication function unit for sending and receiving messages using the overhead of an SDH frame, and a master transmission apparatus to which a command is input for switching from a UPSR to BLSR mode including a path management database, a path decision unit, and an interchange decision unit. The master transmission apparatus to which said command has been input for collecting and storing path setting information of all of the transmission apparatuses in the path management database and sequentially performing processing for deciding on and deleting a long path and processing for interchanging a path on a protection channel to an idle work channel by sending and receiving a message.

Abstract: For the purpose of efficiently determining the transmission capacity of a digital relay transmission path, adjusting the phase between commands and responses, and detecting faults, in the case in which a judgment is made that the image information transmission path capacity between communication apparatuses is smaller than or inferior to the performance of the communication apparatuses, when a training signal for the purpose of performing a circuit check is sent from a transmitting-side facsimile machine, the transmitting-side communication apparatus intentionally sends a failed training signal to the receiving-side communication apparatus, this giving notice of an abnormal termination, in response to which the transmitting-side facsimile machine performs a fallback operation so as to reduce the communication speed to a speed at which relaying is possible between the communication apparatuses before sending the image information.

Abstract: A synchronous receiving method for a selective calling signal is disclosed, in which the selective calling signal comprises a first code of predetermined format which enables a receiving unit to easily detect that information is being sent over a channel, a second code of a predetermined format which succeeds the first code and causes the receiving unit to be synchronized with the information transmitted over the channel, and a third code which succeeds the second code and sends information to the receiving unit. In accordance with the present invention, the synchronization is established with the third code in place of the second code included in the transmitted signal to settle the problems of impaired battery saving efficiency, decreased amount of information and increased transmitting time.