When a coin is inserted into a payphone, the payphone emits a set of tones to ACTS (Automated Coin Toll System). Red boxes work by fooling ACTS into believing you have actually put money into the phone. The red box simply plays the ACTS tones into the telephone microphone. ACTS hears those tones, and allows you to place your call. The actual tones are:

Nickel: 35-160ms 1700hz & 2200hz tone burst, followed by 240ms of silence.
Dime: Two 35-160ms 1700hz & 2200hz bursts, with a spacing of 20-110ms between the bursts, followed by 165 ms of silence.
Quarter: Five 1700hz & 2200hz bursts, with the first and last being 20-100ms in length, and the second through fourth being 20-60ms in length. The spacing between the first and second bursts is 20-110ms, while the spacing between the following bursts is 20-60ms. The tones are followed by 60ms of silence.

Canada uses a variant of ACTSD called N-ACTS. N-ACTS uses different tones than ACTS. In Canada, the tones to use are:

Nickel: 2200hz 0.060s on
Dime: 2200hz 0.060s on, 0.060s off, twice repeating
Quarter: 2200hz 33ms on, 33ms off, 5 times repeating

How do I build a Red Box?

Red boxes are commonly manufactured from Radio Shack tone dialers, Hallmark greeting cards, or made from scratch from readily available electronic components.

To make a Red Box from a Radio Shack 43-141 or 43-146 tone dialer, open the dialer and replace the crystal with a new one. The purpose of the new crystal is to cause the * button on your tone dialer to create a 1700hz and 2200hz tone instead of the original 941hz and 1209hz tones. The exact value of the replacement crystal should be 6.466806 to create a perfect 1700hz tone and 6.513698 to create a perfect 2200hz tone. A crystal close to those values will create a tone that easily falls within the loose tolerances of ACTS. The most popular choice is the 6.5536MHz crystal, because it is the easiest to procure. The old crystal is the large shiny metal component labeled "3.579545MHz." When you are finished replacing the crystal, program the P1 button with five *'s. That will simulate a quarter tone each time you press P1.

You can record the ACTS tones and play them back into the telephone. This is what is done with the Hallmark greeting card. The same concept could also be implemented with a portable MP3 player.

Alternatively, you can build your own circuit using any voice recording chip, such as Radio Shack catalog number 276-1325.

Where can I buy a 6.5536MHz crystal?

Your best bet is a local electronics store. Radio Shack sells them, but they are overpriced and the store must order them in. This takes approximately two weeks. In addition, many Radio Shack employees do not know that this can be done.

Or, you could order the crystal mail order. This introduces Shipping and Handling charges, which are usually much greater than the price of the crystal. It's best to get several people together to share the S&H cost. Or, buy five or six yourself and sell them later. Some of the places you can order crystals are:

Digi-Key 701 Brooks Avenue South P.O. Box 677 Thief River Falls, MN 56701-0677 (800)344-4539 Part Number:X415-ND /* Note: 6.500MHz and only .197 x .433 x .149! */ Part Number:X018-ND

JDR Microdevices 2233 Branham Lane San Jose, CA 95124 (800)538-5000 Part Number: 6.5536MHZ

Alltronics 2300 Zanker Road San Jose CA 95131 (408)94-9774 Voice (408)943-9776 Fax (408)943-0622 BBS Part Number: 92A057

Mouser (800)346-6873 Part Number: 332-1066

Unicorn Electronics 10000 Canoga Ave, Unit c-2 Chatsworth, CA 91311 Phone: 1-800-824-3432 Part Number: CR6.5

Which payphones will a Red Box work on?

Red Boxes will work on telco owned payphones, but not on COCOT's (Customer Owned Coin Operated Telephones).

Red boxes work by fooling ACTS (Automated Coin Toll System) into believing you have put money into the pay phone. ACTS is the telephone company software responsible for saying "Please deposit XX cents" and listening for the coins being deposited.

COCOT's do not use ACTS. On a COCOT, the pay phone itself is responsible for determining what coins have been inserted.

How do I make local calls with a Red Box?

Payphones do not use ACTS (Automated Coin Toll System) for local calls. To use your red box for local calls, you have to fool ACTS into getting involved in the call.

One way to do this, in some areas, is by dialing an Equal Access Code before the number you are dialing. For example, to use 10288 (an Equal Access Code belonging to AT&T), dial 10288-xxx-xxxx. This makes your call a long distance call, and brings ACTS into the picture. There are quite a large number of Equal Access Codes available in most geographic regions.

In other areas, you can call Directory Assistance and ask for the number of the person you are trying to reach. The operator will give you the number and then you will hear a message similar to "Your call can be completed automatically for an additional 35 cents." When this happens, you can then use ACTS tones.

Another operator scam involves calling (800) long distance operators, asking them to connect you, and then playing the ACTS tones. This will get ACTS involved, even on COCOT's!

I have heard that in some areas you can dial local calls as if they were long distance. For example, to dial 345-4587 you would dial 303-345-4587. This does not work on payphones in my area.