ace(7)ace(7)NAMEace - Serial communications interface
SYNOPSIS
controller ace0 at * slot ? vector aceintr
DESCRIPTION
The ace serial line controller provides a serial communications inter‐
face 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.) Cur‐
rently, some processors that use the ace driver limit the serial con‐
sole 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 docu‐
mentation to determine the type of console support your system pro‐
vides.
The driver for the ace interface supports hardware flow control using
the Request to Send (RTS) and Clear to Send (CTS) signals. When hard‐
ware 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 time‐
out), 1, or 2 seconds. Alternatively, you can use the sysconfig com‐
mand to set the same time interval option as follows:
# sysconfig -race 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 debug‐
ging, 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
console terminal local terminal local terminal
SEE ALSOMAKEDEV(8), console(7), devio(7), modem(7), ports(7), tty(7)
Kernel Debugging
System Administration
ace(7)