Instruction manual

5. GPS CONNECTION
5-1 Using a GPS Receiver with the EJ-41U
GPS, the Global Positioning System, transmits signals from a constellation of GPS satellites
orbiting the earth. A GPS receiver uses data from these satellites to determine the current
geographical position of the receiver. This system is widely used in navigation today. The EJ-41U
can transmit the position data taken from the GPS receiver at pre-determined intervals. This
feature allows you to set up a mobile location system, such as a car-navigation system and/or
APRS operations.
5-2 Compatible GPS receivers
The following GPS receivers are compatible with the EJ-41U:
(1) SONY’s IPS-5000 series, IPS-3000 series, PACY-CNV10 and other GPS receivers that output
the data starting with [SONY xxxxxx]. The Sony Car-Navigation system receiver that
generates a data string starting with [SMATC xxxx] may work, but we do not guarantee its
function, as the format of this string is not officially published.
(2) NMEA-0183 compatible output GPS receivers.
The output data from the Sony system is 9600 bps, while most other GPS receivers commonly
operate at 4800 bps but some are capable of 9600. The EJ-41U can accept either output rate but
you must make the appropriate GBAUD setting.
5-3 Data Communication between GPS and EJ-41U:
l Bit-rate: 4800/9600 bps, selected with GBAUD command
l Data length: 8 bit fixed
l Parity: None fixed
l Stop-bit: 1 bit fixed
Flow control is not available. If the PC is connected as a dummy GPS, please loop PC’s CTS and
RTC.
5-3-1 Bit-rate default setting
The bit-rate can be selected as 4800 or 9600 bps. When the RESET command is used, or the
RAM’s back-up data is deleted, the default settings are done by the hardware.
The CPU’s GPS SEL terminal (80
th
pin) determines the default.
When GPS SEL terminal is in [H] position, 9600 bps becomes the default.
GPS SEL terminal is in [L] position, 4800 bps becomes the default.
The status of this pin will be checked when the RESET command is executed or RAM back up is
not present. It does not effect the speed when the system is working properly, or when the RAM
back-up is done with the correct bit-rate setting.