Specifications
2.2 Communications Options
Communications options supported by MicroVAX
and
VAXserver systems
include asynchronous serial controllers, synchronous serial controllers,
and
a
network
controller.
2.2.1
Asynchronous Serial Controllers
Asynchronous serial controllers provide low-speed connections between
peripheral
devices
and
the
system. Asynchronous communications between
the
system
and
the
peripheral depends on recognition of a
pattern
of
start
and
stop bits,
not
on a
time
interval.
2.2.1.1 CXA16 Asynchronous Multiplexer (16 lines)
The CXA16
is
an
intelligent, preprogrammed,
serial
controller
that
can
operate
in
either
DHVll
or
DHUll
mode, depending on
the
setting
of
an
on-board switch. The module contains 16 multiplexed lines.
Functional
Information
Supported
line interfaces
Split
speed
operation
Flow control (XONIXOFF)
Supported
data
formats
Modem control
ErA
RS-423-A/CCrTT
V.10
ErA
RS-232-D/ccrTT
Y.28
DEC
423
All lines
All lines
16
programmable
formats (each
with
1
start
bit)
5, 6,
7,
or 8
data
bits, 0 or 1
parity
bit,
and
1
stop
bit
5
data
bits, 0
or
1
parity
bit,
and
1.5 stop
bits
6,
7,
or 8
data
bits, 0
or
1
parity
bit,
and
2
stop
bits
Parity,
if
enabled,
can
be
either
odd or even.
None
Option Specifications
2-17