Ensure "Use UDP" is checked. Also, confirm the units are set to send device ID too. Those are the add on directions on pages 8 and 9. Please review the settings below and the attached document.
Tap System -> Administration -> GPS in the menu
Tap the “+ Add” button for new Send to Server destination.
Add or Edit Tablet Command
Enter the following settings
Enable this client (is checked)
Client Name: Tablet Command
Server: avl.tabletcommand.com
Port: 12121
Use UDP: checked
Number of stored sentences: 10
Specify Time Interval: (unchecked)
Page2
Choose Language: NMEA
Include System ID: (unchecked)
Prepend System ID: (unchecked)
Which sentence type?
Report NMEA GGA sentences: (checked)
Reporting Intervals (page 3)
Default Time Interval (seconds): 3
Stationary Time Interval (seconds): 300
Stationary Event Threshold (seconds): 30
Stationary Distance Threshold (meters): 20
Distance Interval (meters): 0