Voice data relay apparatus
When a communication system is constructed by use of a plurality of data relay apparatuses of the present invention, it is possible to control an execution/non-execution of a compression/decompression for voice data so that the compression/decompression is not repeatedly executed regardless of a PBX. An ATM multiplexer sends out a transmission pattern to an apparatus adjacent to the ATM multiplexer via a PBX, and stops the compression/decompression of the voice data to relay the voice data transmissively, only when the ATM multiplexer receives the transmission pattern from the adjacent apparatus via the PBX. In other cases, the ATM multiplexer relays the voice data while executing the compression/decompression operation for the voice data.
1. A data relay apparatus connected to a relay path and a communication apparatus-side path Which is a path toward a communication apparatus, the data relay apparatus relaying data between said communication apparatus side path and said relay path, comprising:
detection means for detecting first specified signal which is transmitted by another data relay apparatus from said communication apparatus-side path; and
relay means for encoding data received from said communication apparatus-side path to relay the data thus encoded to said relay path, and for decoding data received from said relay path to relay the data thus decoded to said communication apparatus-side path, when said detection means cannot detect said first specified signal, and for relaying data received from said communication apparatus-side path to said relay path without encoding the data, and for relaying data received from said relay path to said communication apparatus-side path without decoding the data, when said detection means can detect the first specified signal.
2. The data relay apparatus according to claim 1 , further comprising:
transmission means for immediately starting to transmit a second specified signal to said communication apparatus-side path when a call is received from said relay path by said data relay apparatus, and starting to transmit said second specified signal to said communication apparatus-side path after said detection means detects said first specified signal when a call is received from said communication apparatus-side path by said data relay apparatus,
wherein said relay means immediately relays the data received from said communication apparatus-side path to said relay path without encoding the data and relays the data received from said relay path to said communication apparatus-side path without decoding the data, after said detection means detects said first specified signal, when a call is received from said relay path by said data relay apparatus, and said relay means relays the data received from said communication apparatus-aide path to said relay path without encoding the data, and relays the data received from said relay path to said communication apparatus-side path without decoding the data, after passage of a predetermined period of time after said detection means detects said first specified signal, when a call is received from said communication apparatus-side path by said data relay apparatus.
3. The data relay apparatus according to claim 1 , wherein said communication apparatus-side path is a communication channel for data sending/receiving, to/from a PBX (private branch exchange).
4. The data relay apparatus according to claim 1 , wherein said relay path is a VP/VC (Virtual Path/Virtual Channel) set on an ATM (Asynchronous Transfer Mode) network.
5. The data relay apparatus according to claim 1 , wherein said data is voice data, and said encoding is a compression processing of said voice data, and said decoding is a decompression processing of said voice data.
6. A method of encoding/decoding data in a data relay apparatus connected to a relay path and a communication apparatus-side path which is a path toward a communication apparatus, the data relay apparatus relaying the data between said communication apparatus-side path and said relay path, wherein said data relay apparatus is allowed to executer;
a process for detecting a first specified signal which is transmitted by another data relay apparatus from said communication apparatus-side path;
a process for transmitting a second specified signal to said communication apparatus-side path; and
a process for encoding data received from said communication apparatus-side path to relay the thus encoded data to said relay path, and for decoding data received from said relay path to relay the data thus decoded to said communication apparatus-side path, when said first, specified signal cannot be detected, and for relaying data received from said communication apparatus-side path to said relay path without encoding the data, and relaying data received from said relay path to said communication apparatus-side path without decoding the data, when said first specified signal can be detected.