The developers behind the remarkable SeaNav navigation application have written a comprehensive guide to setting up their application on the mac and interfacing with GPS2IP.
You can find the SeaNav setup instructions on their website.

You can connect GPS2IP and SeaNav in two ways
  • Bluetooth Low Energy (BLE) mode
  • A Socket connection

BLE documentation can be found here, and if you're interested, there is a more fundamental look at the priciple differences between BLE and 'regular' Bluetooth here: medium.com.

Here follows how to connect via a Socket connection.

Configure GPS2IP for Socket Mode

When GPS2IP is operating as a socket, it waits and listens for something to connect to it.
Many different devices can connect to GPS2IP simultaneously, and when it transmits data, it will transmit to them all. In this situation, it is easy to receive the same data on different computers on your network.

Step 1

Go into Settings

Scroll down to the bottom.
Select Socket mode.

Step 2

Press     to Enter Socket Settings

Here you can see and edit the Socket Port number.
In this example, the socket port is 11123.

Select your preferred port number, and hit Done to exit.

Hit Done again to exit Settings.

Step 3

Verify Socket mode

You can see that iPhone Server IP can be seen on the front.
Also, that the Port Number you selected in Step 2 is shown.

Step 4

Enable and Connect

Enable GPS2IP with the switch at the top.
If a client connects, the Connections value increases.

Here, we can see one client is connected, and receiving NMEA data.

Test GPS2IP in Socket Mode

Once GPS2IP is set up, perhaps you need to test that your network setup is configured correctly.
We are using a PC or Mac in this example. The process is similar.

  Windows requires using the Command-line
  Mac requires using the Terminal


Step 1

Check Network

Your computer must be on the same network as the iPhone. (Normally wi-fi).

Step 2

Open your Command-line tool

 

 Instructions for opening Windows command-line
 Instructions for opening Mac command-line

Step 3 -

Telnet

Type the command telnet with the IP address and port of your iPhone. 

telnet [address] [port]

In this example, this would be 

Microsoft Windows [Version 10.0.19042.985]
(c) Microsoft Corporation. All rights reserved.

C:\Users\capsicum>telnet 192.168.9.241 11123

If GPS2IP is running in Socket Mode, you should be connected, and see the NMEA data... 

$GPGGA,115922,4825.95722,N,01700.27029,E,1,8,0.9,159.4,M,46.9,M,0,2*77
$GPRMC,115922,A,4825.95722,N,01700.27029,E,0.00,0.00,270521,003.1,W*61
$HCHDG,198.0,,,5.0,E*2C
$GPHDM,198.05,M*00
$GPHDT,203.02,T*06
$GPGGA,115922,4825.95722,N,01700.27029,E,1,8,0.9,159.4,M,46.9,M,0,2*77
$GPRMC,115922,A,4825.95722,N,01700.27029,E,0.00,0.00,270521,003.1,W*61
$HCHDG,198.0,,,5.0,E*2C
$GPHDM,198.05,M*00
$GPHDT,203.02,T*06

Step 3 -

Terminal

Type the command telnet with the IP address and port of your iPhone. 

telnet [address] [port]

In this example, this would be 

capsicum@capsicumMac ~ % telnet 192.168.9.241 11123

If GPS2IP is running in Socket Mode, you should be connected, and see the NMEA data... 

Last login: Thu May 27 10:14:43 from 192.168.9.51
capsicum@capsicumMac ~ % telnet 192.168.9.241 11123
Trying 192.168.9.241...
Connected to 192.168.9.241.
Escape character is '^]'.
$GPGGA,135239,4825.95791,N,01700.27068,E,1,8,0.9,159.4,M,46.9,M,0,2*79
$GPRMC,135239,A,4825.95791,N,01700.27068,E,0.00,0.00,270521,003.1,W*6F
$HCHDG,211.4,,,5.0,E*2A
$GPHDM,211.44,M*07
$GPHDT,216.41,T*05
$GPGGA,135246,4825.95570,N,01700.26781,E,1,8,0.9,159.4,M,46.9,M,0,2*7D
$GPRMC,135246,A,4825.95570,N,01700.26781,E,0.00,0.00,270521,003.1,W*6B
$HCHDG,211.4,,,5.0,E*2A
$GPHDM,211.44,M*07
$GPHDT,216.41,T*05

Step 4

Finished!

At this point, GPS2IP is configured as a socket, and you can connect to it over the network.

Now just configure your navigation app, and start receiving data...

Configure SeaNav

For the most complete answer, get it straight from the horse's mouth on the SeaNav website

If you are still having trouble, please Get in touch - we'll be able to help...