Toll Fraud of the Past

Many years ago, Blue Boxes were one of the phone company's biggest concerns.  Here is how one branch of the old Bell System educated its employees:

Electronic Toll Fraud Devices

There are several different types of electronic equipment which may be generally classified as Electronic Toll Fraud (ETF) devices.  The most significant is the "Blue Box."  The characteristics of each type of device are discussed below.

Blue Box

The Blue Box was so named because of the color of the first one found.  The design and hardware used in the Blue Box is fairly sophisticated, and its size varies from a large piece of apparatus to a miniaturized unit that is approximately the size of a "king-size" package of cigarettes.

The Blue Box contains 12 or 13 buttons or switches that emit multi-frequency tones characteristic of the tones used in the normal operation of the telephone toll (long-distance) switching network.  The Blue Box enables its user to originate fraudulent ("free") toll calls by circumventing toll billing equipment.  The Blue Box may be directly connected to a telephone line, or it may be acoustically coupled to a telephone handset by placing the Blue Box's speaker next to the transmitter of the telephone handset.  The operation of a Blue Box will be discussed in more detail below.

To understand the nature of a fraudulent Blue Box call, it is necessary to understand the basic operation of the Direct Distance Dialing (DDD) telephone network.  When a DDD call is properly originated, the calling number is identified as an integral part of establishing the connection.  This may be done either automatically or, in some cases, by an operator asking the calling party for his telephone number.  This information is entered on a tape in the Automatic Message Accounting (AMA) office.  This tape also contains the number assigned to the trunk line over which the call is to be sent.  The assigned trunk number provides a continuity of information contained on the tape.  Other information relating to the call contained on the tape includes: called number identification, time of origination of call, and information that the called number answered the call.  The time of disconnect at the end of the call is also recorded.

Although the tape contains information with respect to many different calls, the various data entries with respect to a single call are eventually correlated to provide billing information for use by Southern Bell's accounting department.  The typical Blue Box user usually dials a number that will route the call into the telephone network without charge.

For example, the user will very often call a well-known INWATS (toll-free) customer's number.  The Blue Box user, after gaining this access to the network and, in effect, "seizing" control and complete dominion over the line, operates a key on the Blue Box which emits a 2600 Hertz (cycles per second, abbreviated hereafter as "Hz") tone.  This tone causes the switching equipment to release the connection to the INWATS customer's line.  Normally, the 2600 Hz tone is a signal that the calling party has hung up.  The Blue Box simulates this condition.  However, in fact the local trunk on the calling party's end is still connected to the toll network.  The Blue Box user now operates the "KP' (key pulse) key on the Blue Box to notify the toll switching equipment that switching signals are about to be emitted.  The user then pushes the "number" buttons on the Blue Box corresponding to the telephone number being called.  After doing so, he operates the "ST" (start) key to indicate to the switching equipment that signaling is complete.  If the call is completed, only the portion of the original call prior to the emission of 2600 Hz tone is recorded on the AMA tape.  The tones emitted by the Blue Box are not recorded on the AMA tape.  Therefore, because the original call to the INWATS number is toll-free, no billing is rendered in connection with the call.

Although the above is a description of a typical Blue Box operation using a common method of entry into the network, the operation of a Blue Box may vary in any one or all of the following respects:

A.)  The Blue Box may include a rotary dial to apply the 2600 Hz tone and the switching signals.  This type of Blue Box is called a "dial pulser" or "rotary SF" Blue Box.

B.)  Entrance into the DDD toll network may be effected by a pretext call to any other toll-free number such as Universal Directory Assistance (555-1212) or any number in the INWATS network, either inter-state or intra-state, working or non-working.

C.)  Entrance into the DDD toll network may also be in the form of "short haul" calling.  A "short haul" call is a call to any number which will result in a lesser amount of toll charges than the charges for the call to be completed by the Blue Box.  For example, a call to Birmingham from Atlanta may cost $0.80 for the first three minutes while a call from Atlanta to Los Angeles is $1.85 for three minutes.  Thus, a short haul, three-minute call to Birmingham from Atlanta, switched by use of a Blue Box to Los Angeles, would result in a net fraud of $1.05 for a three-minute call.

D.)  A Blue Box may be wired into the telephone line or acoustically coupled by placing the speaker of the Blue Box near the transmitter of the telephone handset.  The Blue Box may even be built inside a regular Touch-Tone telephone, using the telephone's push buttons for the Blue Box's signaling tones.

E.)  A magnetic tape recording may be used to record the blue box tones representative of specific telephone numbers.  Such tape recordings could be used in lieu of a Blue Box to fraudulently place calls to the telephone numbers recorded on the magnetic tape.

All Blue Boxes, except "dial pulser" or "rotary SF" Blue Boxes, must have the following four common operating capabilities:

A.)  It must have signaling capability in the form of a 2600 Hz tone.  This tone is used by the toll network to indicate, either by its presence or its absence, an "on-hook" (idle) or "off-hook" (busy) condition of the trunk.

B.)  The Blue Box must have a "KP" key or button.  "KP" is an abbreviation for a "Key Pulse" tone that unlocks or readies the multi-frequency receiver at the called end to receive the tones corresponding to the called telephone number.

C.)  The typical Blue Box must be able to emit multi-frequency tones which are used to transmit telephone numbers over the toll network.  Each digit of a telephone number is represented by a combination of two tones.  For example, the digit "2" is transmitted by a combination of 700 Hz and 1100 Hz tones.

D.)  The Blue Box must have an "ST" key.  "ST" is an abbreviation for a "start" signal which consists of a combination of two tones that tell the equipment at the called end that all digits have been sent and that the equipment should start switching the call to the called number.

The "dial pulser" or "rotary SF" Blue Box requires only a dial with a signaling capability to produce a 2600 Hz tone.