Not sure what you mean by support.
In KPPP setup, I have tried /dev/modem, /dev/ttyS0, /dev/ttyS1
wit XON/XOFF and KPPP sayes modem ready then initializes it. There is no OK response from the modem and when I query the modem in KPPP the ATIs all come up blank. If I try /dev/ttyS2 or anything else or CRTSCTS I get a modem does not respond message.
Thanks for your help.