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In the "MODBUS over serial line specification implementation guide", RJ45 connectors are recommended. So, how does this comply with the fact that MODBUS RTU supports daisy chaining?

Are there any Modbus RTU RJ45 cables or connectors that make it possible to connect in a daisy chain style? I mean, normally RJ45 is an endpoint.

Thank you for your time.

Most of my experience connecting serial Modbus devices has been with screw terminals or DB connectors. I have seen a few RJ45 drops in my time, and folks like Phoenix Contact and others make DIN rail mountable RJ-45 to screw terminal breakout connectors such that you could run your serial backbone from screw terminal to screw terminal on the connector and then drop to your device with RJ45.

Use a Cat5 and RJ45 breakout to make a RS485 tap.

There are many choices:

1. Phoenix contact's 5543630
http://www.alliedelec.com/Search/SearchResults.asp?N=0& Ntk=Primary&Ntt=5543630

2. Weidmuller's 8555440000
http://www.weidmuller.com/downloads/pdfs/literature/SSB_ G001-G046_Interface_units_GB.pdf

3. Industran's RJ45-U-SM-BRK or RJ45-F-SM-485

http://rj485.com/index.php?main_page=product_info &products_id=7
or
http://rj485.com/index.php?main_page=product_ info&products_id=14

WAGO also has an extensive line of RJ-45 to terminal block interface modules. See the following link:

http://www.wago.com/wagoweb/documentation/navigate/nm7d__ _e.htm

If you don't see what you need. WAGO will also design, build, deliver interface modules to your specifications.

The adapters above are all RJ-45 female jacks (technically '8P8C') to screw terminal blocks.

The NVT NV-RJ45A is an adapter with RJ-45 plug (male) to a screw terminal block.

Dan