If your system is particularly difficult to access physically, another strategy protect it with an Uninterruptible Power Source (UPS) and a
In case recovery becomes necessary, shut down your system using established procedures. Disconnect the power cable and press the power button to drain
capacitance while | power is disconnected. Disconnect and reconnect | modem power, |
and then reconnect | system power to completely reinitialize your | system. |
Transfer of a Modem Session
Because | many | modem | command | variations | exist, the sample modem configuration |
| ||||||||
files located at the end of this | appendix have | been | written to | capture | the l | |||||||||
number of | workable | modem | settings. |
|
|
|
|
|
| |||||
The | modem | command &Dn | (wheren | is | a | number) generally | sets | the modem |
|
| ||||
response | to the Data Terminal Ready | (DTR) signal | from the server's | serial | port. T | |||||||||
desired | response is that | the | modem | will hold a connection while DTR is enabled, | ||||||||||
and | drop | the | connection | when | DTR | is | released. Using this mechanism, the server | |||||||
hangs | up | on a | connection | under | normal | conditions. |
|
|
|
| ||||
Consult your modem manual for its specific response&Dnschemecommandfor. the
Two strategies are available for dealing with the modem's response to DTR:
ŸRecovery
ŸPrevention
Before you use one of these strategies, determine if your server's modem is correctly to respond to DTR.
With the remote terminal connected to serial port 1 and defined as the Primary Console Device, there are two tests you can perform:
1.Will the modem drop the connectionSystemafterinitializationthe complete message displays at the remote terminal?
If Yes, the modem is set up correctly.
If No, try &Dnanothersetting for your server's modem. See your modem manual for this information&Dn. Thecommand appears in three places each in three of the sample modem configuration files, as follows:
2.Will the server's modem disconnect observation at the remote terminal
when the power drops? You | can make this |
by commanding your server | to shut down and |
Appendix D. Modem Configurations183
