Depends which Pactor Modem
you have. As the M710 doesn't have a Pro version maybe you are referring to PTC-II Pro.
If it is the the PTC-Pro or USB models there are GPS
input terminals on the back that forward position data to Airmail through the normal hook-up - enable Position Reports, select Data Input Window & tick "PTC-II NMEA
Other PTC models don't have this facility so you need to provide a separate COM port (with USB/COM adapter) to squirt GPS position into your PC then set Airmail's Position Report Data Input to that COM port.
Once Airmail has your position it will auto update the propagation plug-in.
If you have a ICOM
M710 GMDSS version, there is a "DSC" dB9 connector on the back which should allow GPS feed to it - consult the manual on this - its non-standard serial
port connections. With this version you should be able to input your MMSI as well to allow DSC emergency
Normal M710 doesn't handle DSC
& probably not GPS data either, you need M802 for that.