User manual

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If the device has just been connected or the DSL is still under handshaking, there will not are farend line, farend payload and
V.54.There are no diagnostic function on Ethernet interface model as Ethernet that is looped back would cause a broadcast
storm.
Stand alone NTU, no connection with other NTU:
E1/T1 interface
CO side
Serial interface
CO side
Local Digital Local Digital
Local Local
Remote line Remote line
Remote payload Remote payload
E1/T1 interface
CPE side
Serial interface
CPE side
Local Digital Local Digital
Remote line Remote line
Remote payload Remote payload
After connection both CO side and CPE side:
E1/T1 interface
CO side
Serial interface
CO side
Local Digital Local Digital
Local Local
Remote line Remote line
Remote payload Remote payload
Farend line Farend line
Farend payload Farend payload
V.54
E1/T1 interface
CPE side
Serial interface
CPE side
Local Digital Local Digital
Remote line Remote line
Remote payload Remote payload
Farend line Farend line
Farend payload Farend payload
V.54
About V.54 : An ITU standard (1976) for various loopback tests which can be incorporated into modems for testing the
telephone circuit and isolating transmission problems. Operating modes include local and remote digital loopback and local
and remote analog loopback.