the USR 56k modem model number 0701 REV 5686 at the main with the USR 56K v92 modem modem at the remote does not handshake on any platform.
the v92 at the main and the 0701 rev 5686 at the remote works fine/
the USR model 0648 REV 00568602
and the UST 0701 REV 00568603 work fine at the main with the V92
both hot cats and sneaker villa have the 5686 model.