Doc:MSGB102A0205.doc 15/07/11 P. 16/20
Appendix A – Remote control through modem
Connection via standard modem
To make a remote connection via a switched telephone line the use of a pair of modems is necessary.
Lovato guarantees correct operation of the connection using modems of the following type:
•
3-Com U.S. Robotics 56K model 5630
Though correct operation is possible also with modems of other types, in this manual all the configuration
commands (variables depending on the manufacturer) and the connection diagrams will refer to the above-
mentioned modem model.
Though very simple in conception, connection via modem requires that the installer have a minimum
of experience concerning the problems connected with serial communication, modem programming,
types of telephone lines, etc. In an attempt to simplify the configuration procedure as far as possible,
we have subdivided the operations to be carried out in the following steps:
1. Modem configuration at the ATL end
From the ATL end the modem must be configured before it can be used. Configuration serves to
implement the following functions:
•
Disable the echo
•
Set a communication speed fixed at 9600 baud
•
Permanently store the two previous settings as default at switch on
To make these configurations, the modem to be connected to the ATL will have to be momentarily
connected to the PC with its standard cable. Then start the PM.EXE program (supplied together with this
software) and press the
Program modem
button
.
Wait for the confirmation message and then disconnect
the modem from the PC and connect it to the ATL. The PM.EXE program transmits the following
configuration string to the modem:
AT E0 &N6 &U6 &W0
<CR>
(commands valid for modem model 5630)
If the user is familiar with terminal emulation programs (such as Windows Hyperterminal) this
programming can be done manually without the aid of the PM.EXE program. In this case, it will be
necessary to set the serial interface at 9600 Baud, 8 bit, No parity, 1 stop bit and type in the above string
from the keyboard. On pressing return the modem will answer with OK confirming that programming has
taken place.
2. ATL
configuration
Also the ATL needs a configuration to be able to converse with the modem.
•
Connect the PC to the ATL with the direct RS232 cable code 51C2.
•
Set the password
•
From the Online mode, choose
Modem parameters
from the
Parameters
menu
(see description on
previous pages).
•
Activate the general modem enable (first option at top left).
•
If you want the ATL to call the PC on its own initiative, activate the
enable calls from ATL
and
Connect to
PC
boxes, specifying the PC modem telephone number and the conditions that will determine the call
(against alarm, periodical, etc.)
•
Transmit and store the settings with the
Transmit
button
•
From the ATL front panel, enter Setup menu P7 and set the parameter
P7.03 RS-232 protocol
to
Modbus ASCII + modem
3. System
connection
•
Connect the modem programmed at point 1 with the ATL using the cable code 51C5
•
Connect the second modem to the PC with the standard cable provided with the modem. The PC-side
modem does not require any particular programming (it must be left at factory defaults).
•
Connect both modems to the respective telephone lines. For the first tests you are advised to use two
internal lines in the same office to keep the call under control.
