ADC MDM-TEL
Modem
Document
MDM-TEL Application Note.doc
Page 1 of 16
1
Last reviewed: 03/07/2002
Local
Modem
IBM Compatible
Remote
Modem
PLC
I
ntroduction
This document describes the techniques and procedures we have found to consistently connect a
PC running Directsoft32 to a AutomationDirect PLC through the ADC MDM-TEL modem. It
covers how to set up remote PLC programming and a PLC-to-PLC connection with a MDM-TEL.
The document also describes how to troubleshoot a MDM-TEL connection.
We are not suggesting that other techniques will not work, nor are we suggesting that other
modems will not work. There is no possible way for us to test every manufacturer’s modems and
find the settings and procedures to make those work.
Connecting the modem to the PLC
1.
Recommended PLCs and ports to use
2.
After assembling the proper hardware and cables, there are three phases to setting up the
connection:
1.
Installing the windows modem driver
2.
3.
This document also covers:
1.
DirectSoft32 Setup for Remote PLC Programming
2.
Troubleshooting a Modem Connection
3.
Connecting two Direct Logic PLCs together through the MDM-TEL modem
4.
It is our suggestion that you carefully follow this document first in attempting modem
communication with our PLCs. If this works, you can then try to achieve higher baud rates and
faster throughputs. Phone technology is the key to high performance. There will be some sites
that will not be able to achieve a higher baud rate or even a 9600 baud rate.
If following these steps does not get you connected, please refer to the troubleshooting steps at
the end of this document. If this still does not get you connected, please call our tech support at
(770)844-4200. We will help you in whatever way we can. We would also welcome feedback if
you think that there is any other pertinent information that should be added to this document.
Recommended PLCs and ports to use:
Due to timing problems created by poor quality phone lines, old switches and many other
complications associated with telephone transmissions, we only recommend using the modems
on the “configurable ports” of our PLC’s. These include:
-
D0-05 communication port 2
-
D2-250 communication port 2
-
D2-DCM
-
D3-350 communication port 2
-
D3-DCM
-
D4-450 communications ports 1(RS232 25-pin connector) and 2(RJ-12 on top)
-
D4-DCM
