Using M1 J1 and J2 RS-485 ports?

Out of nothing other than wanting to do a neat job I have used J1 and J2 RS-485 ports on the M1G to connect a input and output expander modules. Both modules are installed in the same 28" housing the M1 is using so the cable lengths are less than 2' (<600mm)

I have a couple of keypads connected to the primary RS-485 port with the screw terminals I was wanting to avoid a rats nest going into this connector hence using J1 and J2 to service the local modules.

Is there any reason or forseeable problem in using the J1 and J2 RS-485 port as I have?

Regards

Fleetz

Won't work, you're not following proper RS-485 protocol by doing such. You need to daisy chain the bus, with no more than 2 branches and terminated at the last device.

If you wanted to keep it "clean", you could bring a branch through the expander and then out to the keypads by connecting them to the expander(s). otherwise you're going to be installing a hub for the bus.

Could you explain how to properly install 2 M1 Keypads using two home runs? I have trouble when addressing the second to Address "2" that I lose communications. I do have jumpers on both keypads.
Thanks
Roofman

If you have 2 keypads you could have the keypads terminated and the elk un-terminated and the elk would be middle of the run. It may make it difficult to add devices in the future though.

Think of the letter "V". The keypads are at the top, the Elk would be at the bottom.

I originally bought my system with 2 keypads and an input expander. Then before I even connected anything I decided to get the hub so I would never have to remember whats terminated and what isn't. I wanted to give myself that "clean" install and ease of troubleshooting that only the hub could. Plus, if I ever have any issues I can just unplug the device and move the connections and terminator. For less than $40 I felt it was worth it for even such a small setup.

I guess it depends on how you look at it. The DBH is a way to basically double your data wiring length. You can have one can with several wires all going to one device OR you can have several devices with 2 data wires or just one data wire at the ends. If you plan your system and your adds to your system you can keep it clean. I also feel the the DBH is a solution for people how don't like do deal with new terms like daisy chain, and termination. The concept of RS-485 is really quite simple if you plan it out. I personally used 22-2pr cabling for all of my data bus devices and would never consider using CAT-5e cabling for security wiring.

True.
However, I looked at it differently and remember I didn't get the hub at first since I have no issues working with the bus and terminations. I needed to start small, but over time want to keep adding to the system; whether it's another keypad, input expander, output expander, whatever. This would mean revisits to my existing work and more planning to tie everything in. With the hub it's a simple crimp and plug. I also knew I wanted to run Cat5e (decided to use stranded that I had for no issue crimps even though I do have solid crimps as well) to any keypad location because I'd probably upgrade it to a tablet. Then all I need to do is unplug from the hub and go right into a network switch. I only plan on keeping the KP2 by the can forever. Plus, the wire runs are short for me so that's a non-issue.

But, as you said, it all comes down to what your needs are and whether it's your house or a customer.
What's the fear of Cat5e cabling? Sure, patch cables go bad but if they're locked in a can I doubt they ever would unless it was poor quality to begin with.

I have to say, I love the dbh. It makes it so fast, so easy, and so adaptable. It does double your effective wire length with each signal going out then back then out then back and so forth, but for 99% of installations that length doesn't present a problem.

So, I can appreciate your sentiments, but for the real world I have to say the dbh is hard to beat.

Seems like this is getting off the OP's original question. That said, here's my take:

For a sheetrock-down professional installation where the installer gets it all working ahead of time and the homeowner is never going to tinker with it, I think the daisy chaining and 2-pair work great - because it's basically a packaged system.

For a DIY install, the Cat5 with the DBH makes more sense IMHO. DIY'ers are more likely to tinker/tweak/expand, and being able to readjust terminations that easily is very valuable both for expansion and for troubleshooting. They're also the ones that are more likely want to "re-use" their Catx wiring for future technologies like video321 suggested.

As for the J1 and J2 ports - i'm pretty sure I saw that those were there for testing by Elk only and not to be used in a permanent installation - but maybe spanky can chime in.

As work2play said:

Temporary Connection "Plug-in" jacks for RS-485 Data Bus (J1 & J2)
Local connection for Data Bus Devices ie: Keypads, etc. for testing purposes only.​

From page 7 of the M1 Installation and Programming Manual

Work2Play said:

As for the J1 and J2 ports - i'm pretty sure I saw that those were there for testing by Elk only and not to be used in a permanent installation - but maybe spanky can chime in.

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W2Play you are correct. This from the manual:

Two (2) quick connect header pin plugs (J1 and J2) along the bottom of the board may be used for temporary purposes I.E. bench testing using a four conductor ribbon cable. Do not use for permanent connections.

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