The service processor uses the ring interrupt request to count the number of rings whenRing Indicate Power-On (RIPO) is enabled. If your modem produces an interrupt ononly the first ring, set Ring Indicate Power-On to start on the first ring. Otherwise, youcan choose to start Ring Indicate Power-On on any ring count.Terminal EmulatorsThe service processor is compatible with simple ASCII terminals, and thereforecompatible with most emulators. When a remote session is handed off from the serviceprocessor to the operating system, agreement between terminal emulators becomesimportant.The server’s operating system will have some built-in terminal emulators. You may alsohave a commercially available terminal emulation. It is important that the local and hostcomputers select the same or compatible terminal emulators so that the keyassignments and responses match, ensuring successful communications and control.For best formatting, choose line wrap in your terminal emulator setup.Recovery ProceduresSituations such as line noises and power surges can sometimes cause your modem toenter an undefined state. When it is being used for dial-in, dial-out or ring indicatepower-on, your modem is initialized each time one of these actions is expected. If oneof these environmental conditions occur after your modem has been initialized, it mightbe necessary to recover your modem to a known state.If your modem communicates correctly with remote users, it is probably in control. Itmay be wise to occasionally change some of the functional settings and then changethem back, just for the sense of security that the modem is communicating, and toensure it has been initialized recently.If your system is particularly difficult to access physically, another strategy is to protect itwith an Uninterruptible Power Source (UPS) and a phone-line surge protector.In case recovery becomes necessary, shut down your system using establishedprocedures. Disconnect the power cable and press the power button to draincapacitance while power is disconnected. Disconnect and reconnect modem power, andthen reconnect system power to completely reinitialize your system.Transfer of a Modem SessionBecause many modem command variations exist, the sample modem configuration fileslocated at the end of this appendix have been written to capture the largest number ofworkable modem settings.The modem command &Dn (wheren is a number) generally sets the modem responseto the Data Terminal Ready (DTR) signal from the server’s serial port. The desiredresponse is that the modem will hold a connection while DTR is enabled, and drop theconnection when DTR is released. Using this mechanism, the server hangs up on aconnection under normal conditions.318 Service Guide
