Replying to Harlan Stenn: > The docs say it connects at 9600, so there is a discrepancy there...
Agreed. > I know several folks have been using the current driver without > problems, so I'm curious about what's going on here. I also know that > some modems will auto-baud, but that might not matter. Some will allow > the modem connect speed to be different from what is used by the serial > connection to the modem. I'm using a TrendNet TFM-561U USB modem -- one of the very few modems I was able to find that is not a "softmodem" / "winmodem" and will work in a Linux system without driver software. I suspect this modem's telco line speed may be tied somehow to the serial connection speed. TrendNet didn't supply any documentation for the AT command set used by this modem, so I tried a "standard" telco line speed command (ATS37=5) -- this command didn't generate an error, but it had no discernible effect in ntpd. Again, when I made the driver open the serial port at 1200 bps, everything worked. > The NMEA refclock uses mode bits 4/5/6 to control the baudrate, but I > don't know if 8 baudrate values will be enough. Should be OK, but we > might be using all the values. I assume the following speeds should be more than sufficient: 300, 1200, 2400, 9600, and 19200; maybe also 38400 and 57600. I'm not sure anyone would ever really need to use 300, but why not. So three mode bits should be fine -- probably use zero (default if no mode is set) for 19200, and 1-6 for the others. Unless at least one of the known modem time services supports or requires a very high baud rate, BTW, I'm unconvinced that supporting anything higher than 9600 is really necessary for this application. Rich Wales ri...@richw.org _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
