Technical data

Page 94 Appendix
dev=term (Terminals)
This is designed for a terminal device. When the device is set to a terminal device,
the incoming port ignores DCD. All outgoing connect attempts are refused.
Wiring required: Only TD, RD, and GND connections are needed, making
it easy to wire up to a terminal.
dev=prn (Printers)
The PortServer treats printers as outgoing devices that ignore DCD. Any incoming
characters are also ignored, until an outgoing connection is made.
Although the device is called prn for printer, it establishes a general purpose output
connection that can be used for any other purpose. When a connection is established
DTR is raised, otherwise DTR is low. Unlike modem device types, there is no two-
second hangup.
Wiring required:
Only TD, RD, and GND connections are generally needed,
making it easy to wire up to a printer.
dev=min (Modem In)
This is designed for a modem for incoming communications only. DTR and DCD
are supported. In this mode, the PortServer ignores all input until DCD appears.
Then it “flushes” all input for 2 seconds to discard messages like RING and
CONNECT, before it spawns a login or attempts a connection.
Anytime DCD drops, the PortServer drops DTR, all connections terminate, and the
user is logged out.
When a user logs out, or (on an auto-connect port) when the remote system drops the
connection, DTR is dropped to hang up the modem. (DTR remains low for 2 seconds
to assure a clean modem disconnect, and then input is flushed to discard
DISCONNECT messages, etc.)
Wiring required:
Modem connections require that TD, RD, DCD, DTR and
GND should always be wired in the cable. With modern
multi-speed, data compressing modems, you probably also
want to wire RTS and CTS for hardware flow control.