View Full Version : A-B Modem Kit
April 26th, 2002, 07:35 PM
I am installing an AB modem kit on a SLC 5/04 for the OEM to send updated chages to. Has anyone has any issues with this system? i can get online with it but lose comms often, what could be the problem? thanks!
April 27th, 2002, 11:52 PM
What BAUD rate are you trying to chit chat with the modems? I've had disconnects at anything above 9600. Try 9600 BAUD? See if that helps.
19,200 seems OK...but was still unstable.
April 29th, 2002, 10:08 AM
Hi, you are right 9600 Baud is the better choice as it is more stable. I just completed a project that I was really pulling my hair out on. I could connect at 9600 baud but would diconnect regularly. I checked and tried everything and it all came down to the phone line on the plc end. The plc was remotely ( I mean REMOTELY!!! ) located and the phone line from the panel to the nearest phone tap was in terrible shape. I tried the setup on a different phone line and it worked great. We had the phone line replaced and haven't had any problems since. Hope this helps.
April 29th, 2002, 05:23 PM
Thanks, i will try a differnt Baud. i know i am well above that rate!
May 28th, 2002, 08:00 AM
Wait! I sense that you might not be understanding what we are trying to say. Using a HIGHER baud rate than 9600 using modems, become UNSTABLE and often DISCONNECT. So slowwwwwwwwwwwwing down the baud rate to 9600 baud stablizes the connection, and in my experience let's me stay connected to the PLC longer without interruption. Hope I explained that ok.
May 29th, 2002, 01:08 AM
I had a tour last Friday of the A-B phone support center at Mayfield Heights, OH, led by none other than the center director, Dave Clark. We went past the modem lab where the A-B kits (as well as a half-dozen other models I saw scattered across the bench) are set up and tested with line simulators.
I asked this very question, about what baud rate was reasonable. Dave said that with perfect-condition phone line simulators he could sustain 38.4 kb, but in the real world 9600 was the most reliable rate by far.
So set that sucker up according to the directions CD that comes with it and you are going to do as well as the phone line will let you.
May 29th, 2002, 07:10 PM
thank you all!