INSTEON: Troubleshooting Communications Errors

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Communication Problems with INSTEON Devices

The INSTEON protocol is a much more robust communication protocol than the older X10 protocol that it replaces. However, INSTEON users will sometimes find that while their INSTEON devices seem to communicate reliably between themselves, the ISY-26 will report "Communication Errors" on their power line network. There are multiple reasons for this:


  • The ISY-26 communicates to the INSTEON devices on a power line network via the SmartHome PLM (PowerLinc Modem). The PLM can be less tolerant of weak INSTEON signals and power line "noise" (interference) than the actual INSTEON switch devices themselves.
  • The PLM and ISY-26 require reliable "acknowledgements" of their "requests" to the INSTEON devices. When these are not properly received for any reason, the ISY-26 will display an error. Sometimes this will prevent the completion of an ISY-26 function.


Due to these characteristics, a power line network must be as free as possible from substantial interference or signal loss, in order for the ISY-26 to provide error-free INSTEON device monitoring and control.


The following tips may be helpful if communication problems are encountered:


  • Use two SmartHome AccessPoints to improve network communications. Place these on opposite legs (sometimes called “phases”) of the power line mains. The AccessPoints provide their own internal utility (as described in their enclosed instructions) to determine if they are on opposite legs of the power line mains. (The older SignaLincs can also be used for the same purpose.)
  • Place the two AccessPoints as close to the power line mains breaker or fuse box as possible. This will give most signals the best chance of being propagated back throughout the entire power line network. This can provide a dramatic improvement in some cases. Again, be certain that the AccessPoints are placed on opposite legs of the power line mains.
  • Stack or “piggy-back” an additional AccessPoint on top of the PLM to improve network communications. The use of a stacked AccessPoint can improve Insteon signal strength to enable the PLM to better receive and send signals. Many users have reported that this is an effective solution. It may help to add this as an additional (third) AccessPoint in addition to the previously mentioned two AccessPoints.
  • Do not plug a PLM into a power strip that has any type of surge-suppression incorporated, as this can weaken the INSTEON signals. Likewise, certain models of GFCI outlets have also been reported to degrade INSTEON signals (this, however, is not true for all GFCIs). To provide for surge protection for the PLM, ISY, and all of your INSTEON devices, consider using a "whole house" surge suppressor. This can often be supplied and installed by your electric power utility for a minimal charge.


The next points are probably some of the most important:


  • Use power line filtering devices (such as the SmartHome Filterlinc) on all potential signal “sinks” and noise generating devices in your home. Devices such as computer power supplies, televisions, home theater systems, etc, can all act as “signal sinks” that degrade the INSTEON signals on your power line network. Conversely, devices such as low voltage halogen lighting, CFLs (compact fluorescent light bulbs), etc, can generate interference patterns on your power line network that can cause the PLM or even other INSTEON devices to miss INSTEON control signals, which get lost in the background noise on the power line. Even if you have previously installed some power line filters on your system, you may find that more may be required if problems still persist. Also, remember that the bottom outlet on the FilterLinc is the “filtered” outlet.
  • For hard-wired halogen or fluorescent lighting, in-line noise suppressors can be used (such as the Levition Noise Block model 6287).
  • Some CFLs are prone to producing much higher levels of power line noise than others. CFLs that are producing excessive line noise can be replaced with those that produce less interference.


Please see "Resolution to my PLM/ISY communication errors (Forum)" for further help and discussion on this topic. More troubleshooting tips.

Related Pages



ISY-26 INSTEON / ISY-99i Series INSTEON : User Guide