config modem clear
From Quake Wiki
|Saved to config.cfg:||yes|
This contains the command to send the modem to reset it. Check your modem manual for alternate settings. This variable is only used if _config_com_modem is 1. Serial communications are not supported in WinQuake or GLQuake and this variable remains unused in those ports, however Linux and DOS ports are capable of serial communication.
|List of console variables | List of console commands|