Multitech MMH900, User Manual

Page: 67 / 200

67
Chapter 5 - Commands
channels to receive EIA control signals through the
MultiMux. Since in normal interactive operations, the
existence of a multiplexer should be transparent to
individual users, the Pass EIA Signals command will
allow terminals to operate as if they were connected
directly to a communications line and not through a
multiplexer. This is done by allowing selected pins
(signals) on one mux to be passed through to
selected pins (signals) on a second remote mux.
The following diagram shows how the Pass EIA
Signals command routes the selected signals:
Composite Link
Facility
(Effect of the
PASS EIA
Signal
F7
Command)
IN 4
IN 20
IN 25
OUT 8
OUT 6
OUT 22
8 OUT
6 OUT
22 OUT
4 IN
20 IN
25 IN
MultiMux
(A)
MultiMux
(B)
F9-F10 PassXon/Xoff
The Pass Xon/Xoff commands, (F9-enable, F10-
disable), are active only if Xon/Xoff flow control is
active. Also called the “Pass Through” commands,
they enable or disable the MultiMux from passing
through Xon/Xoff flow control signals. In the Enable
mode, the MultiMux will obey the Xon/Xoff
commands and pass them on to the channel device.
When this command is enabled, a message "TO
PREVENT DATA LOSS TO A PRINTER OROTHER
PERIPERAL WE RECOMMEND USING FLOW
CONTROL AND PACING, NOT PASS XON," is sent
to the channel device. In the Disable mode, the
MultiMux will obey the Xon/Xoff commands and not
send them to the channel device. The default
condition is for Xon/Xoff Pass Through to be
disabled and it normally should remain disabled.
However, in situations such as a slow data rate of a
channel device, disabling the passing of Xon/Xoff
signals may improve throughput by utilizing buffers
in the mux.