Electronic – Creating a unit to input an array of different computers display/sound and output only 1 with a switch to select

Back when I were a lad, the SN76477 sound effects generator ruled supreme. If you fancy a bit of nostalgia they can be had for just over $9. Admittedly, you need a few other components but they can make a ton and a half of sounds.

http://www.bgmicro.com/ICS76477.aspx

Edit: Just as an afterthought, one of the more irritating circuits that the lads in the electronics club at school used to make up was a 555 oscillator where the timing resistor from Pin 7 to Vcc was replaced by 10 variable resistors with diodes (or LEDs) in series, hooked to the outputs of a 4017 decade counter, which was clocked by another 555 timer. By adjusting the variable resistors and the frequency of the 555 clocking the 4017 you could generate a string of 10 notes in a loop. When this ran at a fast clock speed you got some weird noises.

In the 433 MHz band, there are 69 channels and the list of them and their exact frequencies can be found here.

As far as these modules are concerned, I can't see any mention of channels or exact frequency in the documentation. I know that some (for example this one) modules do mention their frequency, but so far I've been unable to actually find any modules whose frequency channel can be programmed. They do exist, though, since I've seen them in some products.

Some manufacturers (can't find the link at the moment) mention that modules with channels other than default are available for order, but the downside of that is the fact that manufacturers usually do not want to talk to small buyers.