Maybe. You didn’t specify whether the incoming lines must BE at the remote site, or whether you simply need to provide serial port access to some device(s) through a dialup connection.
If the latter situation will meet the need, then I’d suggest doing “reverse” telnet through a router with serial ports (like the “octopus” cables with some cisco routers), or a terminal or communications server.
That way the serial connection is “tunneled” through an otherwise IP network.
Hope that helps,