This specifies the serial port your modem is attached to. On Linux/ x86, typically this is either / dev/ ttyS0 (COM1 under DOS) or / dev/ ttyS1 (COM2 under DOS). If you have an internal ISDN card with AT command emulation (most cards under Linux support this), you should select one of the / dev/ ttyIx devices.
Dynoda hyn y porth cyfresol y cysylltir eich modem ag ef. Ar Linux/ x86, / dev/ ttyS0 (COM1 o dan DOS) neu / dev/ ttyS1 (COM2 o dan DOS) ydi hyn fel arfer. Os bydd gennych cerdyn ISDN mewnol hefo efelychiad gorchymyn AT (cefnogir y rhan fwyaf o gardiau hyn o dan Linux), dylech ddewis un o' r dyfeisiadau / dev/ ttyIx.