Serial communication channels are managed by the devc-ser* family of driver processes. These drivers can manage more than one physical channel and provide character devices with names such as /dev/ser1, /dev/ser2, etc.
When devc-ser* is started, command-line arguments can specify which—and how many—serial ports are installed. On a PC-compatible system, this will typically be the two standard serial ports often referred to as com1 and com2. The devc-ser* driver directly supports most nonintelligent multiport serial cards.
QNX Neutrino includes various serial drivers (e.g., devc-ser8250). For details, see the devc-ser* entries in the Utilities Reference.
The devc-ser* drivers support hardware flow control (except under edited mode) provided that the hardware supports it. Loss of carrier on a modem can be programmed to deliver a SIGHUP signal to an application process (as defined by POSIX).