34
4.3
External Modem Operation,
continued
4. OPERATION
Remote Access Using External Modem
When the remote access feature is enabled, the CFR sends the auto answer
command “ATS0=1” to the modem at the end of the modem initialization (see
terminal menu 521 in section “5.10 External Modem Parameters”). When a remote
host calls the unit, the CFR’s modem will pick up the call on the first ring and send
a “CONNECT” message to the CFR. When the UPS receives this string it knows
a remote call has begun and will stop trying to send any alarms until after the call
is ended.
After establishing the connection, the remote host can access all the RS–
232 menus just as a local terminal can. See section “5. Terminal Communication”
for details. It may be necessary to press the RETURN key to display the first
menu.
If a remote access call is in progress and the remote host drops the
connection, the CFR receives a “NO CARRIER” message from the modem. When
this message is received, the CFR recognizes the call has ended and will resume
sending out any automatic alarms that may have been queued while the remote
call was in progress.
If a remote access call is in progress and no RS–232 commands are
received for more than “Remote Hang up Time,” then the CFR forces modem to
drop the connection by sending the escape sequence, “+++”, followed by the hang
command, “ATH” (see terminal menu “528” in section “5.10 External Modem
Parameters”). This prevents a faulty remote host from tieing up the telephone line
and preventing any other remote calls to be received or automatic alarms to be
sent out.
39
4.4
Using the Standard Interface Device
, continued
Alarm Off Switch
The switch cancels the audible LOW BATTERY WARNING alarm. The
alarm remains disabled until line power is restored and the batteries are recharged.
Fig. 29
Manual Start / (Hold to Test) Switch
The switch is used to start the UPS from battery power whenever AC line
power is not available (“LINE PRESENT” LED OFF). The switch can also be used
to test the UPS’ backup capabilities (“LINE PRESENT” LED ON) without interruption
to the load.
Fig. 30
Output Load Display
The green “25%, 50%, 75%, and 100%” LEDs indicate the loading on the
UPS. Whenever the output load exceeds the rated output of the UPS, the red
“OVERLOAD” LED lights.
NOTE: Each successive LED lights depending upon the load. If the UPS
has a 75% load (displayed), then the 25%, 50% and 75% LEDs will light.
DO NOT EXCEED THE OUTPUT RATING OF THE UPS.
4. OPERATION
MANUAL START
Switch
Fig. 31
OUTPUT LOAD
LEDs
ALARM OFF
Switch
