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14.3.3
Housekeeping
When the modem is idle, the SSBM "pings" (tests for connection) the modem by
sending an "AT" to the modem at five-minute intervals. If the modem does not
respond correctly, by sending either "OK" or "0" to the SSBM, the SSBM attempts
to re-initialize the modem. After a successful re-initialization, the SSBM returns to
the Housekeeping function. If the re-initialization is unsuccessful, two more
attempts to re-initialize the modem are made before the SSBM disables all Call Out
attempts. Re-initialization is then attempted every ten minutes or until the
communications mode is changed by the SSBM front panel controls (or the
modem is successfully re-initialized). For each unsuccessful attempt, the SSBM
logs a modem failure event into the event log. When the modem link is confirmed,
the SSBM communications resume normal operation and Call Out is enabled.
14.4 Hardware Requirements
The following hardware components are required to connect the Remote
Notification function.
•
Modem: Basic external PC modem supporting the following AT commands.
T
&F
E0
N0
Q0
V0
X0
&D0
&K0
&Q5
S0=1 --- Auto Answering.
S37=6--- 2400 Baud.
V0
Y0
NOTE: Consult the modem manufacturer's manual to confirm that the above
commands are supported by your modem.
•
Standard serial cable with a male DB25 connector on both ends.
•
DB25 null modem adapter.
All the above items can be acquired at your local computer products supply store.
An alternative to purchasing a cable is to build your own serial cable using the
following pin out description:
Male DB25
pin 7
pin 2
pin 3
14--4
--- Tone dialing.
--- Load factory defaults.
--- Do not echo characters in command state.
--- Handshake only at speed specified by S37.
--- Return result codes in both originate and answer mode.
--- Display result codes as numbers.
--- Provide basic result codes: CONNECT, NO CARRIER, and RING.
--- Ignore status of DTR signal.
--- Disable local flow control.
--- Communicate in error control mode.
--- Store setup in profile O.
--- Recall profile O on power up.
Male DB25
pin 7
pin 2
pin 2
Powerware 9315 Parallel Capacity/Redundant System with PHP SSBM
164201373 Rev. A
092402
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