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ace(7)


NAME

  ace - Serial communications interface


SYNOPSIS

  controller	  ace0	  at *	  slot ?  vector aceintr


DESCRIPTION

  The ace serial line controller provides a serial communications interface
  on DEC 2000, AlphaStation, and AlphaServer platforms. The serial
  communications ports that are controlled by ace adhere to the RS-232
  standard and can operate at rates from 50 to 115200 baud (see tty(7)).
  These communications ports support serial-line printers, modems, and
  terminals.

  In alternate console configurations (that is, no graphics head), the
  terminal to be the system console must be connected to the port that is
  mapped to /dev/tty00. (See ports(7) for information about mapping
  AlphaStation and AlphaServer port labels to device pathnames.) Currently,
  some processors that use the ace driver limit the serial console port to
  9600 baud, 8-bit, no parity and no modem support. However, some processor
  consoles do support baud rates other than 9600 baud and allow the use of
  modems as console devices. Consult your hardware documentation to determine
  the type of console support your system provides.

  The driver for the ace interface supports hardware flow control using the
  Request to Send (RTS) and Clear to Send (CTS) signals.  When hardware flow
  control is enabled, the flow of input data is controlled by the RTS signal
  and the flow of output data is controlled by the CTS signal.	If the CTS
  signal is off, the driver suspends output to that line until the CTS lead
  is reasserted.  Likewise the driver turns off the RTS lead to tell the
  device connected to the line to stop sending data as a result of congestion
  on the host side.  When the condition clears, the driver turns on the RTS
  lead to tell the device to resume sending data.

  The DCD (carrier detect) timer value defaults to 2 seconds.  This value may
  be changed if your modem hardware requires a different value.	 the change
  can be made in the /etc/sysconfigtab file as follows:

       ace:
       dcd_timer=n

  where n is the time interval in seconds, and can be set to 0 (no timeout),
  1, or 2 seconds.  Alternatively, you can use the sysconfig command to set
  the same time interval option as follows:

       # sysconfig -r ace dcd_timer=[n]

  If you use the sysconfig command, the value will not be preserved when the
  system is rebooted.  To preserve the setting, put the entry in the
  /etc/sysconfigtab file


NOTES

  If you are using the alternate system console to perform kernel debugging,
  you must change the kdebug entry in the /etc/remote file to use /dev/tty01;
  when the kernel is running in debugging mode, no other application can use
  the port. See Kernel Debugging for information on setting up your system
  for kernel debugging.


RESTRICTIONS

  Unless alternative specifications are stated in your system hardware
  documentation, data communications equipment attached to the console serial
  port in alternate console configurations must be set to 9600 baud, 8-bits,
  no parity.  If a serial console is being used, /dev/tty00 cannot be opened
  by another process.  The ace driver enforces this restriction.

  Baud rates greater than 38400 are not supported on the two primary serial
  ports on the DEC 2000 system.	 However, if you use an ISA serial or modem
  card that is capable of communicating at the higher rates, the higher rates
  are supported.


FILES

  /dev/console
      console terminal

  /dev/tty00
      local terminal

  /dev/tty01
      local terminal


SEE ALSO

  MAKEDEV(8), console(7), devio(7), modem(7), ports(7), tty(7)

  Kernel Debugging

  System Administration

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