How to set up the iPAD for sharing data via Wifi with a navigation
program running on a computer.
It is possible to set up the iPad with the iNavx application and a Windows computer in
such a way that the NMEA 0183 data stream received by the PC navigation program via
a COM port is also received by the iPad via Wifi.
In most cases this can be achieved without purchasing any extra equipment.
You may already have a Brookhouse NMEA 0183 multiplexer for combining data from a
GPS, sailing instruments, AIS and other NMEA talkers to a single data stream to feed
PC navigation programs such as Maxsea, Nobeltec, SOB, Maptech, WinGPS, Seaclear,
Oziexplorer or one of the many others via a COM port or via USB.
The multiplexer is not a prerequisite, but in order to feed the iPad via Wifi, all data needs
to be available in the computer as a single combined data-stream received via a COM
port, or a virtual COM port if the data is received via USB or bluetooth.
The following instructions show how to share this data stream with an iPad via Wifi,
thereby creating an extra navigation screen with features that come very close to a full-
featured chart-plotter that can be used anywhere on the boat.
• The (Windows) computer has to support Wifi. Most laptops do. If not, a low-
cost Wifi USB dongle can be purchased for around $25.00.
• Program VSPE (Virtual Serial Ports Emulator). This free program (the 32-bit
version) is kindly made available by Eterlogic and can be downloaded from
their website www.eterlogic.com .
• An iPAD. As external GPS data will be used, the iPad Wifi only model suffices.
The following assumptions are made:
• The Windows version is XP. The procedures for other Windows versions may
• The wireless network card has already been installed and Windows is used for
management of the wireless network. This is often referred to as WZC
(Windows Zero Configuration)
Wireless networks settings on the PC
Go to Control Panel and double-click on Network Connections. The following window
Right-click on Wireless Networks and click Properties.
The Wireless Network Connection Properties window appears.
Select the General tab.
Scroll to Internet Protocol (TCP/IP) and double-click this item. The Internet Protocol
(TCP/IP) Properties window appears (see below).
Tick the fields and enter the values as indicated.
Back to the Wireless Network Connection Properties window
Select the Wireless Networks tab.
Tick Use Windows to configure my wireless network
The Wireless network properties window appears (see below).
Select the Association tab.
Choose a meaningful name for the Network name (SSID) and select other fields as
Optionally, select the Connection tab and tick Connect when this network is in range.
This setting determines whether the network is automatically connected or on demand.
The newly named SSID NMEA 0183 Server will appear under Preferred Networks
Highlight NMEA 0183 Server and click Advanced at the bottom of the window.
The Advanced window appears (see below)
Tick Computer-to-computer (ad hoc) networks only.
Back in the Wireless Network Connection Properties window,
Select the Advanced tab.
The Windows Firewall window appears (see below).
Under the General tab, tick On (recommended)
Select the Exceptions tab.
Click Add Port (see below)
In the Add a Port window, enter the fields as indicated.
Click Change Scope
In the Change Scope window tick My network (subnet) only.
Click OK in the Change Scope window.
Click OK in the Add a Port window
VSPE now appears under Programs and Services (see below).
Click OK in the Windows Firewall window.
Click OK in the Wireless Network Connection Properties window.
Back in the Network Connections window, where we started, right-click on Wireless
Network Connection again and now click View Wireless Netwoks.
Under the available networks (Choose a wireless network) the “network”
NMEA 0183 Server has appeared. (see below).
Later on, we will highlight NMEA 0183 Server and click on Connect. This is not useful
at this stage yet, as we first have to prepare the server program and the iPad.
Prepare the TCP/IP server software (VSPE)
First of all, we need to know which COM port (“real” serial COM port or virtual COM
port) is being used for NMEA input in the navigation program.
This COM-port number can be found in the navigation program’s setup or configuration
section. If it is a virtual COM port for USB or bluetooth communication, make sure that
the USB or bluetooth device is connected to the computer You can also check under
Control panel > System > Hardware > Device Manager > Ports (COM and LPT). Any
currently defined ports are listed here.
In the following discussion, it is assumed that the COM port for NMEA 0183 input is
COM4. If it is a different number, change all occurrences of COM4 accordingly.
It is also assumed, that COM5 is non-existing. If this is not the case, change all
occurrences of COM5 to a non-existing COM port number.
Start the earlier downloaded and installed program VSPE and in the main window, click
on Device in the menu bar at the top of the window. A window with the title Specify
Device Type appears (see below).