When you need to make a call from a pay phone and you don't have any coins or a calling card, you can try to make a collect call from a public phone. First you need to pick up the telephone receiver and press the red rectangle button and then '1541' on a public phone, then you will hear a short comment in Korean saying 'dial the numbers you're calling and #'. After you follow this, then you will hear some tones and the person that you're calling will answer your phone call. Then you should let the person know who's calling. In a few seconds you will also hear another short comment in Korean, saying that 'wait till the person you are calling accepts your phone call', and after that you can talk to the person. It sounds quite complicated but it's not.