The recommended baudrate for NMEA0183 devices is 4800bps. These days, some GPS units are also using 9600bps or even 19200bps for some RTK receivers.
The software allows you to change the port speed of a NMEA0183 channel between the most commonly used baudrates, so other speeds then 4800bps can also be used.
For more information on how to setup a NMEA0183 channel, please refere to the following page:
Configuring an NMEA0183 compatible GPS
