ss(4)ss(4)Namess - Small VAX serial line interface
Syntax
device ss0 at uba0 csr 0x200a0000 flags 0x0f
vector ssrint ssxint
Description
The Small VAX serial line controller is similar to the DZQ11 4-line
communications multiplexer. An interface provides four communication
ports with partial modem control on port 2, adequate for dialup use.
Only port 2 supports modem control (dialup access). All other ports
must be operated as local lines. Each line attached to the serial line
controller behaves as described in and may be set to run at any of 16
speeds. For the encoding, see However, configuration requirements dic‐
tate fixed speed operation of ports connected to the console terminal
and graphics devices.
The Small VAX may be configured as a workstation or a multiuser time‐
sharing system. For the workstation configuration, the ports are used
as follows:
Port Usage
0 Graphics device keyboard at 4800 BPS
1 Mouse or tablet at 4800 BPS
2 Communications (with modem control)/local terminal
3 Serial printer port
For the multiuser configuration, the port usage is:
Port Usage
0 Console terminal at 9600 BPS
1 Local terminal line
2 Communications (with modem control)/local terminal
3 Local terminal or serial printer
For either configuration, a diagnostic console terminal may be con‐
nected to port 3 using a BCC08 cable. For the multiuser configuration,
while the diagnostic console is connected, no other terminal devices
can be connected. When the diagnostic console is in use, the processor
may be halted by pressing the BREAK key.
The selection of which port to use for the console is made during the
processor's power-on sequence and cannot be changed after power on. If
the diagnostic console is connected, it is used; otherwise, the device
connected to port 0 is the console.
For the device, the flags should always be specified as: flags 0x0f
(all 4 lines hardwired). The state of port 2 can be established by
specifying either modem or nomodem as part of the file entry for tty02;
see The default state of port 2 can be controlled by flags bit 2. Set
`flags 0x0f' for a hardwired line, `flags 0x0b' for dialup operation
(wait for carrier).
The driver operates in interrupt-per-character mode (all pending char‐
acters are flushed from the silo on each interrupt). Silo alarm mode
is used by the DZQ11 driver at times of high input character traffic.
This mode is not used by the driver, due to the need to track mouse or
tablet position changes in real time.
VAXstation 3100 Communications and Printer Ports
The VAXstation 3100 has two MMJ (Modified Modular Jack) connectors
located at the rear of the system box. These MMJ connectors allow con‐
nection of terminals, printers, and modems to the VAXstation 3100 sys‐
tem.
The ULTRIX logical names for these connectors are (the MMJ closest to
the power connector) and (the MMJ next to the graphics connector).
Terminals and printers can be connected to either the or MMJ. Modems
can be connected only to the MMJ.
The VAXstation 3100 hardware provides only limited modem control sup‐
port. The DTR (Data Terminal Ready) and DSR (Data Set Ready) signals
are the only modem control signals available at the MMJ. The ULTRIX
device driver for has been modified to allow modems to function with
the limited modem control provided by the VAXstation 3100. For the
modem to function properly, it must be configured to drop DSR when the
carrier drops; that is, the modem should not continuously assert DSR.
Restrictions
The speed must be set to 9600 BPS on the console port and 4800 BPS on
ports used by graphics devices. The console device must be set for
8-bit character length with one stop bit and no parity. The driver
enforces these restrictions; that is, changing speeds with the command
may not always work on these ports.
Diagnostics
ss0: input silo overflow
The 64-character input silo overflowed before it could be serviced.
This can happen if a hard error occurs when the CPU is running with
elevated priority, as the system then prints a message on the console
with interrupts disabled.
Files
console terminal or graphics device
not used
local terminal - multiuser configuration only
dialup or local terminal
printer port or local terminal
mouse or tablet - workstation configuration only
console message window for monochrome workstations
console message window for color workstations
See Alsoconsole(4), devio(4), sm(4), tty(4), ttys(5), MAKEDEV(8)
VAX ss(4)