Simulated telephone

On 8/24/10, Dave Caroline <dave.thearchivist at gmail.com> wrote: I have one - it has two lines. It was a product we sold after bisync and SNA emulator sales tanked. There's an 8048 MCU inside, along with two "SLIC"s (Subscriber Line ICs). The 8048 listens to DTMF tones and provides various simulated faults or a solid connection based on the number you dialed. We also had a 4-line product we bought from some other company to see what other products looked like (all did solid connections; few did simulated line faults). Our faux-exchange (sold under the trademark "COMBOX") was really helpful when I was developing V.25 autodialer code for our flagship product. Mostly, we used "busy" and "never answer" codes to test rejects and timeouts, and it didn't tie up two of our modem lines to do it. As for a simple simulation at home, a 6VDC to 24VDC loop might be enough to pull it off, though some devices won't know to pick up unless you simulate an AC ring. -ethan