User's Manual Part 1

Operation Chapter 4
OEMV Family Installation and Operation User Manual Rev 5B 57
4.1 Communications with the Receiver
Communication with the receiver typically consists of issuing commands through the communication
ports from an external serial communications device. This could be either a terminal or an IBM-
compatible PC that is directly connected to the receiver serial port using a null modem cable. If you
are using an RTK radio it connects to the receiver’s COM port by means of the radio serial cable
supplied with the receiver. It is recommended that you become thoroughly familiar with the
commands and logs detailed in the OEMV Firmware Reference Manual to ensure maximum
utilization of the receiver’s capabilities.
4.1.1 Serial Port Default Settings
The receiver communicates with your PC or terminal via a serial port. For communication to occur,
both the receiver and the operator interface have to be configured properly. The receiver’s COM1,
COM2 and COM3 default port settings are as follows:
• 9600 bps, no parity, 8 data bits, 1 stop bit, no handshaking, echo off
Changing the default settings requires using the COM command.
The data transfer rate you choose determines how fast information is transmitted. Take for example a
log whose message byte count is 96. The default port settings allows 10 bits/byte (8 data bits + 1 stop
bit + 1 framing bit). It therefore takes 960 bits per message. To get 10 messages per second then
requires 9600 bps. Please also remember that even if you set the bps to 9600 the actual data transfer
rate is lower and depends on the number of satellites being tracked, data filters in use, and idle time. It
is therefore suggested that you leave yourself a margin when choosing a data rate (57600 is
recommended for most applications).
CAUTION: Although the receiver can operate at data transfer rates as low as 300 bps, this is
not desirable. For example, if several data logs are active (that is, a significant amount of information
needs to be transmitted every second) but the bit rate is set too low, data will overflow the serial port
buffers, cause an error condition in the receiver status and result in lost data.
4.1.2 Communicating Using a Remote Terminal
One method of communicating with the receiver is through a remote terminal. The receiver has been
pre-wired to allow proper RS-232 interface with your data terminal. To communicate with the
terminal the receiver only requires the RX, TX, and GND lines to be used. Handshaking is not
required, although it can optionally be used. Ensure the terminal’s communications set-up matches the
receiver’s RS-232 protocol. In the case of the DL-V3, Bluetooth (default) and Ethernet are available.
4.1.3 Communicating Using a Personal Computer
An IBM-compatible PC can be set up to emulate a remote terminal as well as provide the added
flexibility of creating multiple-command batch files and data logging storage files. Any standard
communications software package that emulates a terminal can be used to establish bidirectional
communications with the receiver, for example, Hyperterminal or our own graphic user interface
(GUI) program, CDU. All data is sent as raw 8-bit binary or ASCII characters.