I would expect you dedicate one serial port to the Bitsurfer and a second one to an analog modem that in turn is connected to one of the POTS on the Bitsurfer. In the settings string on the Bitsurfer node you'd include the strings that tell the Bitsurfer which end number to assign to each POTS. this way you can have two people calling at any time, either 2 analog or one analog and one digital. Two digital callers at once only works with a card like the Planet ISDN card as the CTB tools for cards allow you to open two CTB ports through one interface which the serial port of the Bitsurfer will NOT allow.
