Tech Support Request - Serial baud rade changes

One of my goals for the forum was to provide a source of information sharing and tech support, so, with that, we have our first tech support style question!

From Jim, W6JVE:

Some of us in the amateur radio game would like to be able to use the serial port on the computer at 45.45 baud, 5 bits per character so we can send and receive 60 wpm RTTY signals through the port. That is not one of the supported baud rates. I don't know where to go to ask that this be changed.

So, is this something that can be done easily? Programatically? Can you help Jim out? If so, post a response! And thanks!

Thanks for sharing the Serial

Andrew321's picture

Thanks for sharing the Serial port information. The .NET Framework V2.0 and higher include the SerialPort class for accessing COM ports, including USB Virtual COM Ports?

Andrew

Serial port information

Jim Haynes's picture

Thanks, I'll try it. 50 baud isn't close enough, but I'm sure 45.44 is.

Serial Port Information

K5TUX's picture

Jim,

Using the Linux stty utility, it is possible to make changes to serial port settings that can closely emulate a RTTY port. Try the following command:

linux> stty 50 cs5 cstopb -F /dev/ttySx

Substitute the proper serial port number for x, where the first port is 0 and so on. The previous command will set your serial port speed to 50 baud with 5 data bits and two stop bits. This is not exactly 45.45 as required by RTTY and may result in high error rates. Using the setserial utility, you can make a tweak to this configuration:

linux> setserial /dev/ttySx baud_base 115200 divisor 2535

This will bring the baud rate of the serial port to 45.44, resulting in about a 0.1% error rate. This may or may not be good enough for your purposes. There are companies that make serial port UARTs that properly handle 45.45 baud, but the standard 16450 or 16550A in your PC is only going to get close.

You might find some more information to help you out here:

http://lkml.indiana.edu/hypermail/linux/kernel/0701.2/1084.html

Hope this helps.

73 de Russ, K5TUX

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