Thanks so much for responding. I think you have answered a few of my beginner questions now!
I am building a MIDI + analog switching system. It will be housed in two units. The first unit, a gutted 1RU router box, will contain a bunch of footswitches and a PIC. The PIC will do two things: 1) send MIDI commands, and 2) send serial data to the second box. In the second box will be the 4053s, controlled by some 74HC595 latches. I plan to send the pulse signals straight over a standard network cable between the two boxes.
So the main box will just be a standard, 5v PIC system. For that I will use a normal 7805 setup. I also need to settle on a ADC multiplexing solution such as R-2R, as I will be using about 30 footswitches.
For the actual switching box, I plan to chain a couple of 74HC595 latches that will drive the control pins of the 4053s. I *think* that the 595 can accept TTL level signals from the PIC, and latch CMOS level outputs. Have to investigate this.
As for the connection, I was just going to connect the PIC output to the 595 input directly over some network cable. This seems to be how RG does it in his remote indicating switcher.
So in short, it is really one circuit, with a PIC at one end and CMOS at the other. My theory level is at the 'shifting ping-pong balls through pipes' stage at the moment, hence the frequent questions about biasing... (BTW I think while reading your last post I finally understood what biasing does... is provides a middle point like a taught string in the centre of a pipe, and the actual guitar signal only 'vibrates' the string by a certain small amount, but being biased it will never hit the edges of the pipe, ie the power rails, and clip. Correct?)
Regarding the resistors, RG's diagram at http://www.geofex.com/article_folders/cd4053/cd4053.htm
only uses one resistor tied to Vref, but you are also using one tied to ground. Could you please explain this? Also, I really don't get what a series cap does. I thought that would eventually stop signal flowing once it was fully charged... or is the point that it will only fully charge if a certain amount of power comes through... kinda like a limiter?
Thanks for drawing a picture. It is my poor understanding of biasing that is generating so many questions about how to chain these CMOS chips together.
Apologies for the extremely long post