by the time I learned about them, red boxes didnt work on telco payphones. we had one customer owned one in a pizza shop, it looked like an old fashioned beige

by the time I learned about them, red boxes didnt work on telco payphones. we had one customer owned one in a pizza shop, it looked like an old fashioned beige desk phone, but had equipment tacked on to take money. That was the only one we could get it to work with.