Redesigned X-10 LM465 Lamp Module.

A major redesign by X-10 of the LM465 plug-in Lamp Module hardware and firmware occurred around the beginning of 2007, with radical changes in characteristics. Unfortunately however the model desig- nation was not changed from LM465, which will undoubtedly result in a lot of user confusion.

A comparison of the characteristics of the original and redesigned LM465 based on my testing can be found at and is reproduced below.

Any additions or corrections will be appreciated. (My email address is good.)

Regards, Charles Sullivan ============================ COMPARISON OF NEW VERSUS OLD LM465 LAMP MODULES by Charles W. Sullivan 22 July 2007

A major redesign by X-10 of the LM465 plug-in Lamp Module hardware and firmware occurred around the beginning of 2007. Unfortunately however the model designation was not changed from LM465, which will undoubt- edly result in a lot of user confusion.

This note will attempt to describe the major characteristics of the new design as compared with the original design. This information was obtained by trial and error measurements on actual units, as X-10 has published nothing about the new design other than a short note in their knowledge-base wiki

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indicating it has a "Soft-Start" feature. The units tested here all have date code sticker 07D17.

The characteristics of the original design LM465 (and rebranded units sold under the RCA, IBM, and Radio Shack labels) remained basically unchanged over the years from those of the original BSR units (brown housing with side thumbwheels). The module responds to X10 signals All_Units_Off, All_Lights_On, On, Off, Dim, and Bright. Alone among dimmer modules manufactured by X-10 and others, it does not support the All_Lights_Off function.

If an original-design module is in the Off state, a received Dim signal will first bring it to full brightness before dimming. The only way to avoid this is never to turn the module Off but instead to dim it to minimum brightness (which is usually visibly indistin- guishable from darkness). Then it can be brightened as desired from that point.

The new design shares many characteristics with the discontinued LM14A 2-way Lamp Module although it remains a 1-way module, i.e., with no status-reporting capability. However it now supports the Extended Code Preset function which allows it to be directly set to any arbi- trary brightness level 0-63. In common with the LM14A it now supports the All_Lights_Off function. Also in common with the LM14A, minimum brightness (at extended code preset level 1) is nowhere near darkness, but about at the level of 15% of line voltage. However this is not a critical limitation now that the module supports the extended code preset function. It is fully Off when turned Off (at extended code preset level 0) by either an Off command or by an Extended Code Preset command. The new design also supports the Extended Code All_Units_On and All_Units_Off functions.

The new design has a "resume" feature similar to the LM14A, i.e., the ability of returning from Off to the previously set brightness level. However this feature is not called into play when the module receives an On signal but when it receives a Dim signal. The dimming continues from that point, so to repeatedly turn Off and then resume the exact same level, it is necessary to follow the Dim signal with a Bright signal of the same magnitude. If the new design receives an On signal when Off, it ramps up gradually over about two seconds, but to full brightness regardless of the previous level.

More details about the characteristics of the new design LM465 will undoubtedly reveal themselves with time.


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Charles Sullivan
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