[EE] RS232 phantom power supply

[William Westfield]

Does anyone have a really good “phantom power” circuit for getting the most out of an rs232 port?
Ideally it would have as inputs multiple ~10mA @+10V or -10V (at least DTR and RTS) (~200mW) and provide 50mA at 3.3V (150mW) or thereabouts…

The nominal goal would be to buffer and send “occasional” serial traffic over BTLE or one of the other “low power radio” standards. I figure with the advances in radios, this should be approaching feasibility.

thanks
Bill W