Patent ID: 7305001

Claim:
An ADSL modem apparatus on a center side that is connected to another ADSL modem apparatus on a remote side, the ADSL modem apparatus on the center side transmitting signals to the ADSL modem on the remote side in a downstream, the ADSL modem apparatus on the remote side transmitting signals to the ADSL modem apparatus on the center side in an upstream, the ADSL modem on the center side comprising: a memory that stores a carrier table for a normal mode that shows that carriers #7 to #31 are assigned to the upstream and carriers #32 to #255 are assigned to the downstream; a handshaker that performs a handshake sequence with the ADSL modem apparatus on the remote side; a determiner that determines whether the ADSL modem apparatus on the remote side supports an original mode, in which some carriers lower than carrier #32 are assigned to the downstream; a rewriter that rewrites the carrier table from the normal mode to the original mode when the determiner determines that the ADSL modem apparatus on the remote side supports the original mode; and an initializer that performs an initialization sequence with the ADSL modem apparatus on the remote side, using carriers that the carrier table, rewritten by the rewriter, shows are assigned to the downstream, the initializer transmitting a PILOT signal to the ADSL modem apparatus on the remote side using the carrier #32 or lower.