[WriteLog] more on com ports

[kr6e]

After working my way through a number of motherboards and serial devices there are several suggestions I would like to offer for those using baudot through com ports such as found in fsk keying.

Try to use motherboards that allow you to reserve interrupts on the PCI buss.  This allows you to "protect" certain cards from interrupt conflicts.  The bios used in Gigabyte boards (among others) allow the user to do this.

The PCI-e buss handles interrupts differently than the PCI buss and many conflicts can be avoided by using 16550/650 cards designed for the PCI-e buss.  The Bytecc BT-PE2S is one example that is a proven card.

Avoid cards that are only an emulation of the 16550 or 16650 UART.  Emulations are very unreliable, especially with data at slow baud rates (emulation missing).

When using multiple comports try to avoid mixing of physical devices requiring more than one common driver.  Use multiple devices of the same type and using the same driver to help avoid driver conflicts.

Not all USB/Serial devices are created equal.   Many do not support a full implementation of the 16550/650 UART.  Many only support 7-8 bit emulations and do not cover all baud rates.  The USB/Serial card marketed by MFJ is only capable of supporting 7-8 bit data (as one example).  You can check the level of emulation of these cables by going into your hardware manager; clicking on the device name; clicking properties; then advanced settings.  The bit level that the 
device is capable of assembling will be displayed.  The Belkin USB/Serial cable is a proven device (Best Buy) as well as the Kensington line of USB/Serial cables.  The Kensington cables
also come with support software.  Again, if using multiple com ports use identical cables to avoid driver conflicts.

Hope some of these suggestions helps others avoid some of the problems I have encountered
along the way.

73  Ben, KR6E