Nigel Goodwin said:
... RS232 to USB converters are EXTREMELY slow, the maximum transfer rate is only 9600 baud!....
According to my experience this is not true. I use them all the time and they go up to 115kbps (most models) or higher (some models).
major drawback for all virtual coms is not the speed, it's the signal power.
they are ok for communication but not when device draws power from serial port (like some pic programmers for example).
some of the converters have multiple RS232 ports. those usually have lower speed limits per com port when compared to same brand / single com port devices. even so they usually meet at least 115kbps.
An example from Moxa:
single port adapter goes to 930kbps
**broken link removed**
four port adapter goes up to 115kbps per port
**broken link removed**
Although we use everything (StarCom, Belkin etc., whatever we can get
fast so anythign you see in Business Depot or Stales or radio Shack ...),
But I really like Moxa products. They usually cost more but they have far superior products.
I am not aware of any other brand offering 15kV ESD protection on COM port (most don't have any).
everyone makes internal multiport cards (such as PCI with 4 or 8 ports)
that even come with isolation - but only on 2 or 4 signals (which they usually don't tell you).
Moxa has 8-port card that is fully optically isolated.