EIA(3) EIA(3) NAME eia - serial communication control SYNOPSIS bind -a '#t' /dev /dev/eia0 /dev/eia0ctl /dev/eia0status /dev/eia1 /dev/eia1ctl /dev/eia1status ... DESCRIPTION The serial line device serves a one-level directory that gives access to the serial ports. Each file set eian ... represents one serial port and includes a data file (eg, eia0), a control file (eg, eia0ctl), and a status file (eg, eia0status). The data file can be read and written to access the corre- sponding serial port. Reads will block until at least one character is available. The ctl file accepts textual commands, via write (see sys- read(2)), that control or condition the serial port for sub- sequent IO: bn Set the baud rate to n. cn If n is non-zero, cause a hangup if the remote drops DCD. dn Set DTR if n is non-zero; otherwise clear it. en If n is non-zero, cause a hangup if the remote drops DSR. f Flush the output queue. h Hangup both input and output queues. kn Send a break lasting n milliseconds. ln Set number of bits per byte to n. Legal values are 5, 6, 7, or 8. mn Obey modem CTS signal if n is non-zero; otherwise clear it. Page 1 Plan 9 (printed 9/8/24) EIA(3) EIA(3) nn Set the output queue to non-blocking, if n is non-zero; otherwise mark it as blocking (the default). In non- blocking mode, if the output queue is full, new output is discarded rather than block the writer until the queue drains. pc Set parity to odd if c is o, to even if c is e; other- wise set no parity. qn Set the limit on input and output queues to n; both queues are initially set to 4k bytes. rn Set RTS if n is non-zero; otherwise clear it. sn Set number of stop bits to n. Legal values are 1 or 2. xn Enable XON/XOFF flow control if n is non-zero; other- wise disable it (the default). Changes to port settings persist between a subsequent close and reopen. The status file can be read for a report of the serial port status. SOURCE /os/port/devns16552.c /os/*/devuart.c /os/*/devscc.c Page 2 Plan 9 (printed 9/8/24)