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4a. I don't know what COM Port my GPS is connected to. What should I do?

Created: 04/24/2007
Modified: 03/04/2008

TOPIC

Electronics Hookup and Configuration


DISCUSSION

There are 4 types of connections between a GPS and the computer:

Standard Serial Connection
For a Standard Serial Connection, the GPS is transmitting NMEA data at 4800 over a serial cable. This cable is connected to a "DB9" connector on the back of the PC - which looks like a "D" with 9 pins (or sockets.) This is the most common installation on "desktop" style PCs.

Serial GPS connected to a USB-to-Serial adapter
In this connection, the Serial Connection (DB9 - described above) from the GPS is mated with a USB-to-Serial adapter that converts the signal into a USB connection. The USB connection is flat and commonly used to interface with mice, printers, digital cameras, and many other computer accessories. Since most laptops lack standard serial connections, this is the most popular option for navigators using a laptop.

USB GPS antenna only connected directly to the PC
Growing in popularity are USB GPS antenna units. These are often the size of a PC mouse (or smaller) and feature a USB cable that connects directly into the computer. Popular models include the GPS-M Pro I GPS, the Zenstar G-Mouse GPS, and the Garmin 18 USB.

Garmin Handheld GPS connected to the PC
Garmin offers a line of handheld GPS units (such as the 76Cx) that connect to the computer via the USB Port. These interface to the PC in a fashion unlike the other three connection types listed above. As such, they are the subject of their own technical document.


With the exception of handheld Garmin GPS units that connect via USB, the Maptech navigation software interfaces with the GPS through the use of a "COM Port". This may be a physical connector on the back of the PC, or a virtual connection provided through a software driver.


I have a Standard Serial Connection. How do I determine the COM Port the GPS is connected to?
The easiest way to determine the COM port is to use HyperTerminal or MTTTY to verify that a NMEA data stream is being received by the computer from the GPS. To do this, set the GPS in NMEA interface mode (most GPSs are always in NMEA Interface mode, only those offered by Garmin may have other modes.) Then, follow one of the following links:
I have Windows XP - Using HyperTerminal to test and verify the GPS connection
I have Windows Vista - Using MTTTY to test and verify the GPS connection

Once you have determined the COM Port, enter this value into the GPS Setup screen of your Maptech navigation software to connect to the GPS.


I have a Serial GPS connected to a USB-to-Serial adapter. How do I determine the COM Port the GPS is connected to?
All USB-to-Serial adapters require software drivers to operate. Thus, a software driver CD-ROM accompanied your adapter. If the CD was missing or has been lost, download the driver from the manufacturer's web site. Once the driver has been installed, click here to determine the virtual COM Port of a USB to Serial Adapter.

Once you have determined the COM Port, enter this value into the GPS Setup screen of your Maptech navigation software to connect to the GPS.


I have a USB GPS antenna only connected directly to the PC. How do I determine the COM Port the GPS is connected to?
All USB GPS antennas require software drivers to operate. Thus, a software driver CD-ROM accompanied your GPS. If the CD was missing or has been lost, download the driver from the manufacturer's web site. Once the driver has been installed, it functions identically to a GPS connected through a USB-to-Serial adapter; click here to determine the number of this type of virtual COM Port.

An exception to this is the Garmin 18 USB GPS. For it to function properly with Maptech products, it must be configured as a NMEA GPS. This is done through a product known as "Spanner." To download the latest version of Spanner, please visit this link to Garmin's web site.

Once you have determined the COM Port, enter this value into the GPS Setup screen of your Maptech navigation software to connect to the GPS.


Finishing the Job: Reading the GPS Stream in Your Maptech Navigation Application
Depending on the Maptech Navigation application you are using, the next step varies. However, the basic concept is now to "tell" it where to find the GPS Signal.

Maptech Chart Navigator Pro (or Maptech Chart Navigator Light)
1. From the 'Tools' menu, select 'Options'.
2. Open the 'Instruments' tab.
3. Press Auto Detect.
(If the GPS signal can still not be located, use Port Settings to specify the COM port determined during the above test. Also, ensure that the Port Interface is set to NMEA and that the correct Baud Rate is selected.)
3. Once the signal is detected, OK the settings changes and press "Go To Boat" on Chart Navigator's button bar to locate the vessel.
Related Technical Document: Configuring Chart Navigator Pro (and Light) to the GPS - Basic Instructions.

Maptech Offshore Navigator (or Offshore Navigator Lite)
1. From the 'Vessel/GPS' menu, choose 'Setup', 'GPS Setup Wizard'.
2. Follow the on-screen instructions.
(If the GPS Wizard can not detect the GPS, select 'Setup', 'GPS' from the 'Vessel/GPS' menu. Set the 'Manufacturer' to 'NMEA - generic' and specify the COM port determined during the above test. Next, click Port Settings and verify the Baud Rate. Then check 'GPS on' and 'Test.')
3. Once the signal is detected, choose 'Position from GPS' from the 'Vessel/GPS' menu, then click 'Follow Vessel' in the lower left-hand corner of the chart window.
Related Technical Document: Configuring Offshore Navigator (or Offshore Nav. Lite) to the GPS - Basic Instructions.

The CAPN
1. Press the large "Click Here To Find GPS" button to the left of the chart window.
2. Press 'Find GPS'.
3. If The CAPN does not find the GPS in it's search of COM Ports, click the Port Settings button and adjust the appropriate COM Port and Baud Rate. Then Click SAVE
(In older versions, If The CAPN can not detect the GPS, exit The CAPN, and open the GPS.INI file found in the 'C:\Capn Voyager' folder. Edit this file to include the COM port and Baud Rate determined during the above test. Save the changes and restart The CAPN)
Note: Also, in older versions of The CAPN, you can not use COM ports higher than 9. If your GPS is connected to COM 10 or higher, reset the drivers for that port so that a lower COM port is used.
Related Technical Document: Configuring The CAPN to the GPS - Basic Instructions.
Related Technical Document: What COM Ports are valid for use with The CAPN?

Maptech Chart Navigator (free chart viewer)
Chart Navigator Viewer is for printing and planning with BSB nautical charts. It can not be used for plotting a position in real-time. GPS functionality is limited to the transfer of routes, waypoints, and tracks to and from handheld GPS units. To configure Chart Navigator Viewer for this purpose, choose 'Setup', 'GPS' from the 'GPS' menu.
Related Technical Document: Configuring Chart Navigator (Free Viewer) to the GPS - Basic Instructions.

Maptech Terrain Navigator (or Terrain Navigator Pro)
1. From the 'GPS' menu, choose 'GPS Setup Wizard'.
2. Follow the on-screen instructions.
(If the GPS Wizard can not detect the GPS, select 'Setup' from the 'GPS' menu. Set the 'Manufacturer' to 'NMEA - generic' and specify the COM port determined during the above test. Also, ensure that the correct baud rate of the GPS is selected in Port Settings. Then press 'Close')
3. Once the signal is detected, choose 'GPS Tracking', 'Start Tracking' from the 'GPS' menu.
Related Technical Document: Configuring Terrain Navigator (or Pro) to the GPS - Basic Instructions.





 


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