The opamp can be another similar part, and the +9V can be less/more depending on what you have available. However, many simple electret circuit are pretty high impedance, so you might want to use a simple opamp buffer: Or transmit audio data from one PC to the other, combine and then send to headset.įor the microphone, you would hope that the internal amplifier might be low impedance enough to drive both PC inputs okay. If you were comitted to doing this, you would probably have to design your own adapter (using a couple of microcontrollers, FTDI chips, or similar)įar easier is to go analogue as Chris suggests, this would only require a simple mixing circuit.
Plus it may put undue stress on the output drivers, as they will be fighting against each other (known as bus contention) USB is quite tolerant of problems like this, so it's unlikely you have damaged anything. If you have two hosts on the same bus, they will both be trying to send data at the same time and things will get very confused. The host (PC in your case) initiates all transactions, which means the device must wait for a signal from the host if it has data to send. USB 2.0 (the most commonly used at the moment) is a half duplex differential bus, which means that the host and device take it in turns to send/receive. This won't work, and will not be a good idea for the PCs.
