m241: Document serial port hardware

Hint that yellow m241 uses SiLabs CP210x. Red m241 is dead to us and the whole company is even more dead.

diff --git a/xmldoc/formats/m241.xml b/xmldoc/formats/m241.xml
index 52c34ab636b3d1e62d2c4a602509fa1696df670a..fa6602256a74ade57a973cbdbd77616a17ae4108 100644 (file)
--- a/xmldoc/formats/m241.xml
+++ b/xmldoc/formats/m241.xml
@@ -1,15 +1,25 @@
 <para>
-       The Holux m241 is a small datalogger using the MTK chipset, with 
-       a couple small differences in the binary format. In its default 
+       The Holux m241 is a small datalogger using the MTK chipset, with
+       a couple small differences in the binary format. In its default
        configuration, it can store ~100000 trackpoints with very limited
-        data; to configure extended logging you can use the BT747 open 
-       source software 
+        data; to configure extended logging you can use the BT747 open
+       source software
          <ulink url="http://bt747.wiki.sourceforge.net">bt747</ulink>
         Waypoint storage is possible only if "recording reason" (RCR) is enabled in the settings.
 </para>
 <para>
-       Holux GPSport 245 is a datalogger with display suitable for cycling, walking and running. 
-        It can store ~200k trackpoints with limited data. The m241 and m241-bin format is 
+  The m-241 came in two models. The yellow one, popular with photographers,
+  internally used the Silicon Labs CP210X chipset to transform the internal and
+  inaccessible serial port to the USB port that was familiar on the side. The
+  drivers for that port can be found with
+  <ulink url="https://www.silabs.com/products/mcu/Pages/USBtoUARTBridgeVCPDrivers.aspx">SiLabs CP210x serial port drivers</ulink>. The red and white one existed
+  very briefly before Holux went out of business. GPSBabel does not work with
+  the red and white one.
+
+  </para>
+<para>
+       Holux GPSport 245 is a datalogger with display suitable for cycling, walking and running.
+        It can store ~200k trackpoints with limited data. The m241 and m241-bin format is
         able to automatically detect GPSport 245 data and handle the differences from Holux 241 devices.
         Note: GP245 does not log any quality of the position.
 </para>