On Saturday, April 06, 2013 at 1:30 PM, Cory Smelosky wrote: On 6 Apr 2013, at 16:26, "Johnny Billquist" <bqt at softjar.se> wrote: However, it is nice that simh now can associate a physical serial port with a simulated one. How transparent is it? I mean, can you change the speed of the physical serial port by doing the programming of the simulated one? Actually, if the DZ device is set for 'modem control', modem enabled signaling, all aspects of the connection are dynamically under control of the simulated OS. This full signaling capability is part of an 'extended' API which the device simulation needs to be modified to support (the DZ was modified, the VH (aka DHV) was not). The VH can attach particular lines to host serial ports, but the line speed, etc. must be statically configured when the attachment is made. ATTACH DZ has an option for specifying baud rate. I broke SIMH when I tried to set it to 300 baud though. ;) Please elaborate (offline) the details so whatever you saw broken can be fixed! Thanks. - Mark