I need help understanding the physical interface between the microchip PIC16F73 I am using and the X10pro psc05 bidirectional power line interface. The info in the MEL PBP manual is very sketchy about this command and the electronic interface to the psc05. My PBP manual only talks about a TW-523, which is no longer available, but was supposedly replaced by the newer psc05. When I get onto the x-10 site, it says they offer the suggested schematic for interfacing with the psc05, but no further information will be provided. I see their schematic for the psc05 has opto-isolators. The Xout command, they say, should go through a pnp inverter and then into the opto-isolator. Although I have had good success with the MEL pbp "Xin" instruction, I cannot make the "Xout" instruction control any equipment through the psc05. In fact, the red led on the psc05 just dims, rather than blinking, as it does when I command the same codes out over a hand-held X-10 remote. I have tried direct coupling the PIC pin (capable of 30 mA) right to the pin-4 on the RJ-11 and also taking it there through X10pro's suggested pnp inverter circuit, also through a 7404 inverter, also through a 74xx buffer. The psc05 has a 1K resistor in series with the led in the opto-coupler, so it should only pull about 3.5 mA, when conducting. Does the Xout signal really need inverting on the way over to the psc05? When X10pro shows the suggested OEM interface (12 page, free download), I assume they do not know what equipment I will be using to drive that pin, so how can they know I will be using a PIC, or the MEL PBP "Xout" instruction? I cannot seem to make this puppy work. I am driving the psc05 from the PortB.1 pin on my pic (not open-drain), configured as a digital output. The zero-crossing input pin works properly on my pic, when driven by the psc05's RJ-11, pin1, for the "Xin", so it should also be working for the "Xout"...... I am stumped. Any suggestions out there??? Please assist if you can!!!