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Chapter 2: Installation
Serial Ports
The V104s offers position and heading data via two full-duplex (bi-
directional) RS-232 serial ports. In addition to outputting data, these ports
are used for firmware upgrades.
Selecting Baud Rates and Message Types
When selecting your baud rate and message types, use the following
calculation to determine your baud rate for your required data throughput.
Messages * Message output rate * Message length (bytes) * bits in byte
Ex: 5 * 10Hz * 40 bytes * 10 = 20,000 bits/sec
For information on message output rates refer to GPS Technical Reference
available from the Hemisphere GNSS website at
www.hemispheregnss.com.
Configuring the Ports
You may configure Port A or Port B of the GPS receiver to output any
combination of data that you want. Port A can have a different configuration
from Port B in terms of data message output, data rates, and the baud rate of
the port. This allows you to configure the ports independently based upon
your needs. For example, if you want one generalized port and one
heading-only port, you can configure the ports as follows:
• Port A to have GPGGA, GPVTG, GPGSV, GPZDA, and GPHDT all
output at 1 Hz over a 9600 baud rate
• Port B to have GPHDT and GPROT output at their maximum rate of
10 Hz over a 19200 baud rate
A personal computer (PC) typically uses a DB9-male connector for RS-232
serial port communications.
Note: For successful communications use the 8-N-1 protocol and set the
baud rate of the V104s’s serial ports to match that of the devices to which
they are connected. Flow control is not supported.
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