Oliver Schulz wrote:
Another issue to consider is the availability of software interfaces provided by the OS to access the RS232 modem control lines or to accessThis is not a problem (with ordinary user-level privileges), every serial terminal program needs to use the handshake lines, after all. Both Windows and Unix/Linux systems provide API's for serial port access. I'd guess that Graeme is quite familiar with them, since argyll supports serial port devices. :-)
Yes, modem lines can be sampled, although I don't think the software interface in Argyll is setup this way. It sounds easy enough to create an interface of some sort, although using software sampling is always a dodgy proposition on a multi-tasking operating system. Another option for instance would be to buy something like this <http://www.ftdichip.com/Products/EvaluationKits/DIPModules.htm>, and put it in "bit banger" mode to plug it into USB. Graeme Gill.