Modem into a DH485 Network??

Just wondering if anyone has had success trying to modem into a DH-485 network. Since RS-Linx only seems to support modems over DF1, I'm thinking about an alternative.

Could I use two external modems and a USB adapter(1747-UIC) to do the connection. I would run the USB adapter to the RS232 connection over to the serial port on an external modem (Sixnet?), then dial out using a handset (instead of computer modem) to connect to another external modem with it's serial port connected to the serial port on an AIC+ adapter, which gets me into the network. I'm guessing the hardest part would be ensuring that the connection stays active on both modems.

Anyone have any thoughts?? I'm hoping someone might have an easier solution? Thanks.

See links below.

http://www.plctalk.net/qanda/showpost.php?p=268426&postcount=3

http://www.plctalk.net/qanda/showpost.php?p=21027&postcount=8

I couldn't even follow the chain of ideas there... backwards through a USB/RS232 converter then through a handset... but then I got to "Modem to AIC+" and that I understood.

As my previous posts, cited by Mickey, said: DH-485 absolutely cannot work with any sort of modem. It's got to be DF1.

Your best bet is to use a standalone DF1/DH485 interface or use the venerable 1747-KE module in an SLC-500 chassis.

This third-party device from EquusTek is probably the simplest way to do this if you don't have a SLC chassis handy:

http://www.protocolconverter.com/product_GW1000-DH4851.html

Comment: Don't feel bad if you can't follow the feature/model combinations from EquusTek. The website descriptions are FUBAR; get a printed data sheet and confirm in person before purchasing.

I was afraid of the timing issues. The customer insisted on 5/03 processors. We have one master 5/03 and 4 slave 5/03 communicating over DH485. They were hoping I could tie into the AIC+ installed in all panels to remotely program the units.

If I remember correctly, there is no way to pass through either, if I were to add an ethernet or DF1 port to the Master Rack.

Thanks for your help guys.

Actually, the SLC-5/03 does support DF1 to DH485 Passthrough.

The controller has to be relatively modern; this feature was added in OS302 FRN8 in 2004 or so. The status bits S:34/0 and S:34/5 both have to be set =1 for passthrough to work, and you configure RSLinx as though it was connected to a 1747-KE.

RA Knowledgebase document 26885 has a good example of using Passthrough with MSG instructions.