T.I.R

5.2.2.1 Modem Communication Terminology

AT command set – fairly standardized command set used by modems. Most commands to the modem start with ”AT” and end to a carriage-return.

Carriage-return – the ASCII code 0x0D, that is commonly used as string/line termination.

D-sub – the 9-pin communication connector in PW9355.

FORS – software running in a service center host computer. Whenever there is some active alarm requiring service attention, the UPS calls to FORS.

Also, FORS may periodically call to the UPS to request the state and history log from the unit.

Modem – a communication device that allows using serial communication over public telephone lines.

XCP – the communication protocol used with PW9355.

X-Slot – an extension card slot. PW9355 has two X-Slots, 1 and 2.

5.2.2.2 Introduction

This document describes the modem support in PW9355. The modem handling is designed to work with FORS service system and any modem that uses the industry standard ”AT” command set. When the UPS requires service attention, it automatically calls to the service center. Then, using the normal XCP, the service center host computer requests data from the UPS. The service center may initiate the call to the UPS.

This makes modem handling in the UPS simple. The UPS is only responsible for:

• Detecting the condition that requires service attention: this is done by correctly selecting and setting the alarms, which cause the UPS to make the call.

• Making the call: this is done by periodically sending a correctly set command string to the modem. This is repeated until the connection is created, or predefined number of tries has been made.

• Responding: while the connection is active, the UPS responds normally to any XCP monitoring commands. All control commands are disabled, until the required password is given.

• Disconnecting the line: this is done by periodically sending a correctly set hang-up string to the modem, until the modem responds expectedly.

The 9355 modem support uses binary XCP. The ASCII Computer Mode (ACM), which is mentioned in the XCP Protocol Specification, is not used.

5.2.2.3 Communication Speed

The communication speed for the modem communication channel (between the UPS and the modem) must be set correctly. Modems may be able to detect this speed automatically, but the recommendation is to use a fixed speed in the modem.

• The factory setting for both communication channels is 19200bps.

5.2.2.4 Lock Communication to D-Sub

Normally the serial communication of channel 2 is done via the X-Slot 2. When the D-sub is used for communication, then channel 2 is automatically switched there from the slot. When the D-sub isn’t used anymore, the channel 2 is switched back to the X-Slot 2.

The setting disables the automatic switching between the two, and locks the communication to the D-sub. This removes the possibility of losing the first command/message when a communication session is started with the UPS.

This setting is recommended if channel 2 communication is used only by the D-sub. For example, this is the case when the modem is installed to the D-sub while the serial communication in the X-Slot 2 is unused. This setting has no effect on communication channel 1.

5.2.2.5 Control Commands Inhibition

This setting is for security: it disables all control and configuration commands coming from the communication channel. There is an independent setting for each channel. This is settable using the front panel LCD menu only.

When this setting is ”not allowed” for the modem communication channel, all UPS control and configuration commands via the modem are disabled. To allow any control of the UPS via the modem, this setting must be set to

”allowed” for the communication channel, and the correct modem communication password must be given during the modem session.

Note:

The factory setting for both channels is ”not allowed”.

5.2.2.6 Modem Communication

This setting tells the UPS if a modem is connected to the UPS. Zero value means that no modem is installed. Other values define the communication channel where the modem is installed. All modem handling and communication restrictions (”AT” commands and password requirements, for example) are directed to this channel. The other communication channel operates normally.

When the modem is installed and this parameter is correctly set, the UPS will automatically make a call when an event requires it. The call is made to the number defined by the modem call number string.

• The factory setting is zero, ”modem not installed”.

5.2.2.7 Modem Call Number

This is a string that holds the call command and the cal number. The maximum string length is 39 characters. To initialize a modem call, the UPS simply sends this string to the modem; it must include all (commands/numbers) the modem needs to make the call.

For example, the phone number of the service center computer is 123-4567:

Modem call number = ”ATDT1234567”.

The string may also include other modem control commands.

• The factory setting is an empty string, only the automatically added carriage-return is sent to the modem.

5.2.2.8 Modem Initialization String

This string is used to initialize the modem. Normally, the correct configuration is stored into the modem non-volatile memory, and this string only directs the modem to reset itself and use the stored configuration. The maximum string length is 47 characters.

While the modem handling is in the modem idle state, the UPS firmware

automatically sends the initialization string to the modem every 15 minutes. The modem initialization can be commanded using a XCP parameter or with the

front panel. Using this command causes the modem to be initialized immediately. If there is an open modem call, it will be hung up.

• The factory setting is ”ATZ0.”

5.2.2.9 Modem Communication Password

When a new modem call begins, only UPS monitoring is allowed; this means commands that retrieve normal ”user” data from the UPS, meters, status, alarms, history log, and so on. To make any UPS control or configuration via the modem, a password must be given. The given password is valid only during the present modem session, and it must be given again when a new modem call is made.

The password is given using the XCP Configuration Field command. The password is a write-only string for the user. Service may change the password.

The maximum string length is 9 characters. In addition to giving the correct password, the control commands must be allowed for the communication channel.

• The factory setting is an empty string - the user must use the XCP Configuration Fields command to fill the empty string.

5.2.2.10 Modem Hang-up String

This string is used for “escaping” the modem to command mode and hanging-up the line. The maximum string length is 31 characters. All other characters except comma ’,’ (ASCII 0x2C) are sent to the modem. The comma character causes a 2 second pause before continuing.

• The factory setting is ”,+++,ATH0”.

5.2.2.11 Modem Message String

When this string is set, (its length > 0) then the operation changes when the UPS makes the call. About 5 seconds after the connection is made

(”CONNECT”), the UPS sends this string to the line, then sends the internal alarm message string and number (in ASCII format) that requested the call, then the UPS disconnects the line and returns to Modem Idle state.

The maximum string length is 31 characters, or preferably 63 bytes if there is room in the EEPROM.

The factory setting is an empty string.