I fiddled a bit with the "Auxilliary Power Supply DC 12V" input to my FIOS BBU.
The barrel connector seems to be a 0.15 inch barrel (approximately 6mm), center positive. I clipped the connector and cable off an obsolete wall wart, and proceeded. This is the same power connector as some of the older Nokia cell phones, IIRC. I set up a lab bench power supply with current and voltage limits, and connected it to the cable. When I increased the voltage above 12.5V , the "Auxilliary Power Source" light on the front panel lit up. The BBU drew less than 10mA. I dialed it up to 13.5V, about what a car battery puts out, and set the current limit to 5 amps. Since the unit draws 20W from the line in normal operation, I assumed that would be enough. I pulled the line power input to the BBU, the unit went on battery as intended. I pulled the internal battery connection, hoping it would use the auxiliary power instead of the internal battery, and the BBU shut down, without drawing current from the auxiliary jack and bench supply. It might have been a startup surge, so I tried again with 0.086 farads across the supply. Again, shut down, no current from the bench supply. I don't want to try a car battery directly, too much current if something shorts. So - a mystery. Perhaps there is some protocol on the wire to the approved external device. For extended life, use an external UPS on the line input, I guess. Keith -- Keith Lofstrom [email protected] Voice (503)-520-1993 KLIC --- Keith Lofstrom Integrated Circuits --- "Your Ideas in Silicon" Design Contracting in Bipolar and CMOS - Analog, Digital, and Scan ICs _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
