Serial Port: <tt>/dev/gps<i>u</i></tt>; 4800 baud, 8-bits, no parity<br>
Serial Port: <tt>/dev/gps<i>u</i></tt>; symlink to server:port (for nmead) Features: <tt>tty_clk</tt></p>
<h4>Description</h4>
<p>This driver supports GPS receivers with the <tt>$GPRMC</tt> NMEA output string by default. Alternately the <tt>$GPGGA</tt> or <tt>$GPGLL </tt>may be selected.</p>
<p>The driver expects the receiver to be set up to transmit a <tt>$GPRMC</tt> message every second.</p>
<p>The accuracy depend on the receiver used. Inexpesive GPS models are available with a claimed PPS signal accuracy of 1 <fontface="Symbol">m</font>s or better relative to the broadcast signal. However, in most cases the actual accuracy is limited by the precision of the timecode and the latencies of the serial interface and operating system.</p>
<p>If the Operating System supports the PPSAPI, RFC-2783, it will be used.<br> </p>
<p>The various GPS sentences that this driver recognises look like this:<br>
Alternate GPS sentences (other than <tt>$GPRMC</tt> - the default) may be enabled by setting the relevent bits of 'mode' in the server configuration line<br> * server 127.127.20.x mode X<br> bit 0 - enables RMC ( value = 1)<br> bit 1 - enables GGA ( value = 2)<br> bit 2 - enables GLL ( value = 4)<br>
multiple sentences may be selected<br>
<p>The driver will send a <tt>$PMOTG,RMC,0000*1D<cr><lf></tt> message each time a <tt>$GPRMC</tt> string is needed. This is not needed on most GPS receivers because they automatically send the <tt>$GPRMC</tt> string every second and will only work on GPS receivers that understand the <tt>$PMOTG</tt> string. Others will just ignore it.</p>
<h4>Setting up the Garmin GPS-25XL</h4>
Switch off all output with by sending it the following string.
