STAT-4, STAT-8, AND STAT-24
10
When delivered, the non-volatile memory of the stat mux is already loaded with the default configuration, so
the stat mux is configured in accordance with the factory settings. You may have to select again the default
configuration (INIT) again in the following cases:
• After an error during the configuration session, which either prevents communication between the control
terminal and the stat mux, or is difficult to trace and correct.
• The description of the configuration loaded into the stat mux has been lost, so it’s not possible to enter the
configuration mode in the NOR mode. To avoid this inconvenience, always keep a record of the last
configuration parameters (a typical record form is shown in
Appendix B
).
After you load the default configuration by setting the jumper to INIT and powering up or resetting the stat
mux, the default configuration becomes the current stat mux configuration. Return the jumper to the NOR
position to allow configuration.
2. PIN 21 ON-OFF jumper. Pin 21 of the standard RS-232 interface can serve either as a signal quality
indication (SQ) line, or as a remote loopback command line. The actual function depends on the specific
model of modem you’re using, and a jumper allows adapting the stat mux to the modem connected to the
composite (main) link connector.
The jumper has two positions:
•
PIN 21 ON: Set the jumper to this position when the modem uses pin 21 as a remote loopback
command line. This connects the internal stat mux pin 21 driver to this pin, and allows you to control
this modem function using the diagnostics screen.
•
PIN 21 OFF: Set the jumper to this position when the modem uses pin 21 as a signal quality indication
output. Use this position whenever in doubt about the actual function of the pin in the specific modem
model you use. When the jumper is in this position, you no longer have control of the modem’s remote
loopback function from the diagnostics screen. The factory setting is OFF.
3. GND jumper. This jumper controls the connection between the signal ground lines to the chassis ground
lines. The installation manager determines the appropriate position.
The jumper has two positions:
• C (connect)—signal ground connected to chassis ground.
• D (disconnect)—signal ground disconnected from chassis ground.
Factory setting is D (Disconnect).
3.4 How to Set the Jumpers
WARNING
Avoid electric shock! Always turn the power switch off and disconnect the power cable
from mains before opening the stat mux.
Follow these steps to set the jumpers:
1. Access the printed circuit board of the stat mux by opening the screw (or screws) fastening the top cover
to the case, and remove the top cover.
