RS-485 is current loop rather than voltage. Easily converted to RS-232 and back.
Modbus is a communication protocol using formatted text strings. It’s pretty simple to read and write programatically. I have written a few BASIC programs to do so (I date myself). Any programming language that can process text strings can speak Modbus with a little work. Modbus+ is a higher speed synchronously timed protocol that is considerably more involved to work with. Mark > On Aug 19, 2020, at 4:29 PM, ch...@wbmfg.com wrote: > > It is a way to get in and set parameters and options, like remote start or > remote loading. > > From: Cameron Crum <> > Sent: Wednesday, August 19, 2020 1:57 PM > To: AnimalFarm Microwave Users Group <> > Subject: Re: [AFMUG] OT odd data connection > > Just curious what kind of data you need for an air compressor? > > On Wed, Aug 19, 2020 at 11:51 AM TJ Trout <t...@voltbb.com <>> wrote: >> apc uses rj10's for usb.. >> >> On Wed, Aug 19, 2020 at 9:46 AM Ken Hohhof <af...@kwisp.com <>> wrote: >>> Apparently modbus is a data protocol, not a physical layer standard, but >>> yes it could go over RS485. I don’t see how a simple cable could convert >>> from USB to RS485. I sure hope for $200 you are getting a dongle, not an >>> expensive cable. >>> >>> The connector you are referring to, is that a 4 pin modular plug, like used >>> on the handset cord for a phone? >>> >>> From: AF <af-boun...@af.afmug.com <>> On Behalf Of ch...@wbmfg.com <> >>> Sent: Wednesday, August 19, 2020 11:27 AM >>> To: af@af.afmug.com <> >>> Subject: [AFMUG] OT odd data connection >>> >>> On one of my large portable air compressors, there is a data port. They >>> sell an adapter cable for about $200 It adapts it to USB. The program >>> that you use to talk to it makes reference to modbus. >>> >>> The data port has 4 pins. RJ-10 4p4c connector. >>> +5 with enough current to light an incandescent light bulb. >>> +5 low current >>> +5 low current >>> Ground >>> >>> This sounds like USB host to me. One of my sons think it is RS-485 >>> >>> I don’t think USB would be happy on a RJ-10 and utp wire. Maybe it would. >>> Maybe I am just buying a piece of wire with two connectors on the ends. >>> >>> The controller it plugs into is $2000 so I don’t want to experiment on >>> that. Be interesting to see the adapter cable when it gets here. See if >>> there are any active components. I would have probably just wired it up to >>> a USB and tried it if my son had not made the modbus/RS485 comment. >>> >>> Any guesses? >>> -- >>> AF mailing list >>> AF@af.afmug.com <> >>> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >>> <http://af.afmug.com/mailman/listinfo/af_af.afmug.com> >> -- >> AF mailing list >> AF@af.afmug.com <> >> http://af.afmug.com/mailman/listinfo/af_af.afmug.com >> <http://af.afmug.com/mailman/listinfo/af_af.afmug.com> > > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com
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