User's Manual

Chapter Five Specifications
Man_455U Rev 1.0 Page 39
4.7 Configuration Examples
Typical Applications
The following section describes some typical applications and the configuration of the
modems involved.
4.7.1 Data Logger Network with Central Computer
In this application, the computer connects to each logger on a regular basis, and uploads
information from the logger. The logger protocol does not support error checking, and the PC
application software is designed to work with telephone modems. The PC software issues
ATD commands to the central modem to make connection with each logger. When it has
finished communicating with the logger, it issues an ATH command to terminate the
connection.
4.7.1.1 Central Modem configuration
AT&M1 – Configure Acknowledged Mode
AT&E1 – Enable Error checking
AT&U1 – Set unit address to 1.
4.7.1.2 Remote Modems configuration
AT&M1 – Configure Acknowledged Mode
AT&E1 – Enable Error checking
ATS0=1 – Enable Auto Answering on first attempt.
AT&U2, AT&U3, etc – Set unit address to 2, 3, 4, etc for each remote modem.
4.7.2 Unsupported Protocol, with broadcast messages and repeaters.
This example demonstrates how to operate with an unsupported protocol, and demonstrates
how to broadcast messages to the entire system.
This example incorporates a single station connected to Master host device, two repeater
stations with connected slave host devices, and three remote stations each with a connected
slave host device. The master station is address 1. The two repeater stations are address 2 and
3. The remote stations are addresses 4, 5 and 6.
Remote station 4 communicates directly to the master station. Remote stations 5 and 6
communicate with the master via repeater stations 2 and 3 respectively. Messages from the
Master host device must be delivered to all of the slave devices, and messages from each of
the slave devices must be delivered to the master station.
This example uses operating mode 0, which routes all messages according to the path set with
the &Z0 command.
The host protocol is packet based, with message packets of up to 100 bytes. The master
station initiates all communication, and waits for a response from the slave devices.
4.7.2.1 Master Host site Modem configuration
AT&M0 - Configure mode 0 – Unacknowledged mode.