CHAPTER 2: METER OVERVIEW COMM OPTION 2: INTERNAL MODEM WITH DIAL-IN/DIAL-OUT OPTION
EPM 9450/9650 ADVANCED POWER QUALITY METERING SYSTEM – INSTRUCTION MANUAL 2–3
2.4 Comm Option 2: Internal Modem with Dial-in/Dial-out Option
The following sections describe the optional Comm Option 2 Internal Modem.
2.4.1 Hardware Overview
Comm Option 2 for the EPM 9450/9650 meter provides a direct connection to a standard
telephone line. No additional hardware is required to establish a communication
connection between the meter and a remote computer. The RJ11 Jack is on the face of the
meter. A standard telephone RJ11 plug can connect the meter to a standard PSTN (Public
Switched Telephone Network).
The modem operates at up to 56k baud. It supports both incoming calls (from a remote
computer) and automatic dial-out calls when a defined event must be automatically
reported. With the device configured with Comm Option 2, the meter has dial-in capability
and provides remote access to other Modbus-based serial devices via the meter’s RS485
Gateway over your phone line. The meter recognizes and responds to a Modbus Address of
1. With any other address, the command passes through the gateway and become a
virtual connection between the remote Modbus master and any Modbus slave connected
to the RS485 Gateway.
The modem continuously monitors the telephone line to detect an incoming call. When an
incoming call is detected, the modem will wait a user-set number of rings and answer the
call.
2.4.2 Dial-In Function
The modem can be programmed to check for a password on an incoming call. If the
correct password is not provided, the modem hangs up on the incoming call. If
several unsuccessful incoming call attempts are received in a set time period, the modem
locks out future incoming calls for a user-set number of hours.
When an incoming call is successfully connected, the control of communication is passed
to the calling software program. The modem responds to computer
commands to download data or other actions authorized by the meter passwords.
Refer to the GE Communicator Instruction Manual for instructions on programming the
modem.
2.4.3 Dial-Out Function
The Dial-Out Function (Comm Option 2) is intended to allow the meter to automatically
report certain conditions without user intervention. The modem polls the meter to
determine if any abnormal or reportable conditions exist. The modem checks
programmed meter conditions and programmed events (set in GE Communicator
software) to determine if a call should be placed.
If any of the monitored events exist, the modem automatically initiates a call to a specified
location to make a report or perform some other function. For log full conditions, the meter
automatically downloads the log(s) that are nearing the full condition.
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