Brian H

I have a few I rebuilt and a spare new one myself.

The Insteon web site now says the 2413S serial PLM is discontinued and no longer supported. This should only effect the users still using a ISY994i. InsteonSerial Modem Interface (PLM)This item has been discontinued. Please see our USB Modem Interface.

Correct . The Insteon sales site. Says the 2413S PLM is discontinued and no longer available.

If I remember correctly. The add on IR Module was needed for the IR module to work. After I got my IR module. UDI had to download something to my ISY994i.

A factory reset before installation has fixed issues for some users. Some had test stuff in them and not reset before sales.

Bright LED is only one symptom. It can still be bad with a bright LED. Best to do what you thought. Ticket so UDI can help you troubleshoot.

Did you power cycle the Eisy also? The PLM is most likely only checked for a boot up. Is the LED on the side of the PLM on at about its normally brightness? Sounds like the PLM has failed or is almost completely failed. How old is it? Sticker on the back should give you information.

Thank you for the update.

The SH10A is receive only and will not send an acknowledge back. You probably are seeing the PLM acknowledging the command. Since the PLM sends the command back to verify it was valid and sent.

The X10 commands require a short delay between commands. Like the address has to be sent and then a short (not much but don't have exactly known) time the bright or dim command. I am not a programing type so if the slight delay maybe needed. I can't say how to do it. That maybe but not for sure your problem. The ISY controller that worked maybe running slower than the eisy that doesn't work. With the short delay long enough with the ISY controller.

The small siren. Need the X10 address sent and then the bright or dim command. Did you send the address than a small pause to the dim or bright? Do you have any other X10 devices that are still OK? If others also stopped working then I would suspect something changed power line problems.

I saw your question on the X10 forum and I agreed. In my post there. Try moving the module to different places to see if you have a power line signal issue.

I have one of the early released Insteon Siren modules and I believe X10 was not supported.

5.3.4 was the last ISY994i firmware. If you have a Z wave card. Depending on which version you have. Series 300 or 500. 5.3.4 was only for series 500.

Yes it has failed. Power cycling and working again for a short time is one of the failure modes we see. If the eisy behaves like the older ISY994i. It will only check for a PLM at boot time. It may have to be rebooted to again check for a PLM. If it thinks it is not communicating.