I really appreciate the effort you have gone to. I've seen the help you have provided many places around the net, and I really do appreciate all you do.
Your XTBM information is rather interesting. Here is what is happening here currently without the benefit of any diagnostic data.
Set up includes 4 ToggleLinc Dimmers all set to X10 Address (I think C12). One, I will call the master is connected to the load, the others have no load connection. All are on the same circuit.
The X10 is being controlled remotely by RF transmitters to an RR501 on a different circuit and a CM15A on another circuit. I have an XTB-IIR at the panel and my XTBM usually shows little to no noise.
The RR501 and the CM15A both do ON-OFF's properly. The ON turns on the lights to the preset level I programmed in the Master ToggleLinc.
Dimming works correctly from the RF devices. I do not have a PC hooked up to my CM15A so I have not tried dimming from that device. When I get my XTBM back, I will also hook up ActiveHome Pro and at least have the activity log for some more information. The RR501 is just sending a string of standard DIM's so no surprise that it is OK. I am guessing that ActiveHome Pro will not be so kind unless I redefine the switches some way to stop it sending the extended dim command.
Locally, the master ToggleLinc operates the lights as expected ON OFF, and Dim and Brighten.
The slave Toggle Lincs (3) will turn the lights on and off. On is to a preset brightness, however, I am not sure if this is the setting in the master settings or from my attempt to program the slave switches.
None of the slave switches will dim or brighten the lights correctly. When the toggle is help up (or down) nothing happens. If I toggle it a few times, the lights do change but in one or two large steps and at random, including getting brighter or dimmer regardless of whether I was toggling up or down. All slaves behave the same way. This is what has me confused because it is the X10 communication between the Insteon Switches that seems to be the problem.
I have a couple of ideas of how I am going to try to isolate this once I get my XTBM. First, I want to try to substitute a new switch that I will program with a load attached so that I do not run into the same programming issues. I am sure that I do not have three bad switches and one good one, so this is just to isolate the programming difficulty I had because I was unable to control the brightness at the slave switches when programming and that is required for the preset as well as the ramp time.
It will also help me confirm or refute my only theory and that is that all the Insteon switches are not transmitting the X10 dim commands in a way that they can understand. By using a new switch, I will also be able to determine whether the problem is a result of my programming efforts or a software problem in the switch. My suspicion is the latter because other than setting the X10 address, I had done nothing before I first encountered the dimming problem.
As an aside, do you know if the slave switches use their own programmed parameters for the ramp time and initial dim level? I was hoping that they would use those of the master switch since it is connected to the load, but I know that when I first installed them, their ON was at full bright.
Rereading your XTBM results, I had another thought. Is it possible to link the switches as Insteon devices without needing a controller? Only the master needs an X10 address if I could link the slave switches as Insteon.