####################################### # # # # # ======== =\ = ====== # # == = \ = = # # == = \ = ====== # # == = \ = = # # == = \= ====== # # # # # # # # ''''''''''''''''''''' # # # # # # > Written by Dr. Hugo P. Tolmes < # # # # # ####################################### Issue Number: 12 Release Date: November 19, 1987 This entire issue is an article about blue boxing. Notice: This article is full of errors that most phreaks will catch. $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$ TITLE: The Blue Box an Ma Bell FROM: Radio Electronics DATE: November 1987 -WHEN BLUE AND READ MEANT THE TRASHING OF MA BELL............ Before the Breakup of AT&T, Ma Bell was everyone's favorite enemy. So it was not suprising that so many people worked so hard and so successfully at perfecting various means of making free and untraceable telephone calls. Whether it ws a Red box used by Joe and Jane College to call home, or a blue box used by organized crime to lay off untraceable bets, the technology that provided the finest telephone system in the world contained the seeds of its own destruction. The fact of the matter is that the blue box was so effective at making untraceable calls that there is no estimate how many calls were made or who made them. No one knows for certain whether Ma Bell los revenues of $100,$100-million, or $1 billion on the Blue Box. Blue Boxes were so effective at making free, untraceable calls that Ma Bell didn't want anyone to know about them, and for many years denied their existence. They even went as far as strong-arming a major consumer-science magazine into killing an article that had been prepared on the Blue and Red boxes. Further, the police records of a major city contain a report concerning a break-in at the residence of the author of the article. The only item missing following the break-in was the folder containing copies of one of the earliest Blue-Box designs and a Bell-system booklet that described how subscriber billing was done by the AMA machine-a boklet that Ma Bell denied ever existed; Fig. 1 proves otherwise. Since the AMA (Automatic Message Accounting) machine was th means whereby Ma Bell eventually tracked down both the Blue and Red boxes, we'll take time out to explain it. Besides, knowing how the AMA machine works will help you to better understand Blue and Red Box "phone phreaking." WHO MADE THE CALL? Back in the early days of the telephone, a customer's billing originated in a mechanical counting device, which was usually called a "register" or a "meter." Each subscriber's line was connected to a meter that was part of a wall of meters. the meter clicked off the message units, and once a month someone simply wrote down the meter's reading, which was later interpolated into message-unit billing for the subscriber's who wunit. (Flat-rate subscriber's could make unlimited calls only within a designated geographic area. The meter clicked off message units for the calls outside the area.) Because eventually there were too many meters to read individually, and because more subscribers started questioning their monthly bills, the local telephone companies turned to photography. A photograph of a large number of meters served as an inconstestable record of their reading at a given date and time, and was much easier to convert to customer billing by the accounting department. As you might imagine, even with photographs billing was cumbersome and did not reflect the latest technical developments. a meter didn't provide any indication of what the subscriber was doing with the telephone, nor did it indicate how the average subscriber made calls or efficiency of the information service (how fast the operators could handle requests). So meters were replaced by the AMA machine. One machine handled up to 20,000 subscribers. It produced a punched tape for a 24-hour period that showed, among other things, the time the phone was picked up for (went off-hook). One other point, which will answer some questions that you're certain to think of as we discuss the Red and Blue boxes: Ma Bell did not want person outside their system to know about the AMA machine. The reason? Almost everyone had complaints-usually unjustified-about their billing. Had the public been aware of the AMA machine they would have asked for a monthly list of their telephone calls. It wasn@t that Ma Bell feared errors in billing; rather, they were fearful of being buried under an avalanche of paperwork and customer complaints. also, the public believed their telephone calls were personal and untraceable, and Ma Bell didn't want to admit that they knew about the who, what, and where of every call. and so Ma Bell always insisted that billing was based on a meter that simply "clicked" for each message unit; that thee was no record, other than for the long-distance calls, as to who called whom. Long distance was handled by, and the billing information ws done by and operator, so ther was a written record Ma Bell could not deny. The secrecy surrounding the AMA machine was so pervasive that local, state, and even federal police were told that local calls made by criminals were untraceable, and that people who made obscene telephone calls could not be tracked down unless the person receiving the call could keep the caller on the line for some 30 to 50 minutes so the connections could be physically traced by technicians. Imagine asking woman or child to put up with almost an hour's worth of the most horrendous obscentities in the hope someone could trace the line. Yet in areas where the AMA machine had replaced the meters, it would have been a simple, though perhaps time-consuming task, to track down the numbers called by any telephone during a 24-hour period. but MaBell wanted the AMA machine kept as secret as possible, and so many a criminal was not caught, and many a w by obscene calls of a potential rapist, because existance of the AMA machine was denied. As a sidelight as to the secrecy surrounding the AMA machine, someone at Ma Bell or the local operating company decided to put the squeeze on the author of the article on Blue Boxes, and reported to the Treasury Department that he was, in fact, manufacturing them for organized crime- the going rate in the mid 1960's was supposedly $20,000 a box. (Perhaps Ma Bell figured the author would get the obvious message: Forget about the Blue Box and the AMA machine or you'll spend lots of time, and much money on lawyer's fees to get out of the hassles it will cause.) The author was suddenly visited at his place of employment by a Treasury agent. Fortunately, it took just a few minutes to convince the agent that the author was really just that, and not a technical wizard working for the mob. but one conversation led to another, and the Treasury agent was astounded to learned about the AMA machine. (Wow! Can and author whose story is squelched spill his guts.) According to the Treasury agent, his department had been told that it was impossible to get a record of local calls made by gangsters; the Treasury department had never been informed of the existance of automatic message accounting. Needless to say, the agent left with his own copy of the Bell System publication about the AMA machine, and the author had an appointment with the local Treasury-Bureau director to fill him in on the AMA machine. That information eventually ended up with Senator Dodd, who was conducting a congressional investigation into, among other things, telephone company surveillance of subscriber lines- which was a common practice for which there was detailed instructions, Ma Bell's own switching equipment ("crossbar") manual. THE BLUE BOX The Blue Box permitted free telephone calls because it used Ma Bell's own internal frequency-sensitive circuits. When direct long-distance dialing ws intorduced, the crossbar equipment knew a long-distance call was being dialed by the three-digit area code. The crossbar then converted the dial pulses to the CCITT tone groups, shown in Taple 1, that are used for international and trunkline signaling. (Note that those do not correspond to Touch-Tone frequencies.) As you can see in that table, the tone groups represent more than just numbers; among other things there are tone groups identified as KP (prime) and ST (start)- keep them in mind. When a subscriber dialed an area code and a telephone number on a rotary-dial telephone, the crossbar automatically connected the subscriber's line to a long-distance trunk, converted the dial pulses to CCITT tones, set up electronic cross-country signaling equipment, and recorded the originating number and the called number on the AMA machine. the CCITT tones sent out on the long-distance trunk lines activated special equipment that set up or selected the routing, and caused electro-mechanical equipment in the target city to dial the called telephone. Operator-assisted lls worked the same way. The operator simply logged into a long-distance trunk and pushed the appropriate buttons, which generated the same tones as direct-dial equipment. The button sequence was KP (which activated the long-distance equipment), then the complete area code and telephone number. At the target city, the connection was made to the called number but ringing did not occur until the operator there pressed the ST button. The sequence of events of early blue Boxes went like this; The caller dialed information in a distant city, which caused his AMA machine to record a free call to information. When the information operator answered, he pressed the KP key on the Blue Box, which disconnected the operator and gave him access to a long-distance trunk. He then dialed the desired number and ended with an ST, which cuased the target phone to ring. For as long as the conversation took place, the AMA machine indicated a free call to an information operator. The technique required a long-distance information operator because the local operator, not being on a long distance trunk, was accessed through local wire switching, not the CCITT tones. CALL ANYWHERE Now imagine the possibilities. Assume the Blue Box user was in Philadelphia. He would call Chicago information, disconnect from the operator with a KP tone, and then dial anywhere that was on direct-dial service: Los Angeles, Dallas, or anywhere in the world if the Blue Box could get the international codes. The legend is often told of one blue Boxer who, in the 1960's, lived in New York and ahd a girl friend at college near Boston. Now back in the 1960's, making a telephone call to a college town on the weekend was even more difficult that it is today to make a call from New York to Florida on a reduced-rate holiday using one of the cut-rate long-distance carriers. So our Blue Boxer got on an international operator's circuit to Rome, Blue Boxed through to a Hamburg operator, and asked Hamburg to patch through to Boston. The Hamburg operator thought the call originated in Rome and inquired as to the "operator's" good english, to which the Blue boxer replied that he was an expatriate hired to handle calls by American routists back to their homeland. Every weekend, while the Northeast was stranged by reduced-rate long-distance calls, our Blue Boxer had no trouble sending his voice almost 7,000 miles for free. VACUUM TUBES Assembly plans for blue boxers were sold through calssified advertisements in the electronic-hobbyist magazines. One of the earliest designs was a two-tube portable model that used a 1.5 volt "A" battery for the filaments and a 125-volt "B" battery for the high voltage (B+) power supply. The portable blue box's functional circuit is shown in Fig. 2. It consisted of two pase-shift oscillators sharing a common speaker that mixed the tones from both oscillators. Switches s1 and s2 each represent 12 switching circuits used to generate the tones. (No, we will not supply a working circuit, so please don't write in and ask- e user placed the speaker over the telephone handset's transmitter and simply pressed the buttons that corresponed to the desired CCITT tones. It was just that simple. Actually, it was even easier than it reads because Blue Boxers discovered they did not need the operator. If they dialed an active telephone located in certain nearby, but different, area codes, they could Blue Box just as if they had Blue Boxed trhough an information operator's circuit. The subscriber whose line was Blue Boxed simply found his phone was dead when it was picked up. But if the Blue box conversation ws short, the "dead" phone suddenly came to life the next time it ws picked up. Using a list of "distant" numbers, a Blue Boxer would never hassle anyone enough time to make them complain to the telephone company. The difference between Blue Boxing off of a subscriber rather than an information operator was the the Blue Boxer's AMA tape indicated a real long-distance telephone call- perhaps costing 15 or 25 cents- insted of a freebie. Of course, that is the reason why when Ma Bell finally decided to go public with the "assisted" newspaper articles about the Blue Box usuers they had apprehened, it was usually some college kid or "phone phreak". One never read of a mobster being caught. Greed and stupidity were the reasons why the kids were caught. It was the transistor that led Ma Bell going public with the Blue Box. By using transistors with RC phase-shift networks for the oscillators, a portable blue Box could be made inexpensively, and small enough to be used unobtrusively from a public telephone. The college crowd in many technical schools went crazy with the portable Blue Box; they could call the folks back home, their friends, or get a free network (the Alberta and Carolina connections- which could be a topic for a whole separate article) and never pay a dime to Ma Bell. Unlike the mobsters who were willing to pay a small long-distance charge when Blue Boxing, the kids wanted it, wanted ti all free, and as they used the information operator routing, and would often talk "free-of-charge" for hours on end. Ma Bell finally realized that Blue Boxing was costing them Big Bucks, and decided a few articles on the criminal penalties might scare the Blue Boxers enough to cease and desist. But who did Ma Bell catch? The college kids and the greedies. When Ma Bell decided to catch Blue Boxers she simply examined the AMA tapes for calls to an information operator that were excessively long. No one talked to an operator for 5, 10, 30 minutes, or several hours. Once a long call to an operator appeared several times on an AMA tape, Ma Bell simply monitored the line and the Blue Boxer was caught. (Now do you understand why we opened with the explanation of the AMA machine?) If the Blue Boxer worked from a telephone booth, Ma Bell simply monitored the booth. Ma Bell might not have known who originated the call, but she did know who got the call, and getting that party to spill their guts was not problem. The mob and a few Blue Box h even thousands) knew of the AMA machine, and so they used a real telephone number for the KP skip. Their AMA tapes looked perfectly legitimate. Even if Ma Bell had told the authorities they could provide a list of direct-dialed calls made by local mobsters, the AMA tapes would never show who was called through a Blue Box. For example, if a bookmaker in New York wanted to lay off some action in Chicago, he would make a legitimate call to New Jersey. Nowhere would there be a record of the call to Chicago. Of course, automatic tone monitoring, computerized billing, and ESS (Electronic Switching Systems) now makes that all vitually impossible, but that7s the way it was. You might wonder how Ma Bell discovered the tricks of the Blue Boxers. Simple, they hired the perpetrators as consultants. While the initial newspaper articles detailed the potential jail penalties for apprehended Blue Boxers, except for Ma Bell employees who assisted a Blue Boxer, it is almost impossible to find an article on the resolution of the cases because most hobbyist Blue boxers got suspened sentences and/or probation if they assisted Ma Bell in developing anit-Blue Box techniques. It is asserted, although it can't be easily proven, that cooperating ex-Blue Boxers were paid as consultants. (If you can't beat them, hire them to work for you.) Should you get any ideas about Blue Boxing, keep in mind that modern switching equipment has the capacity to recognize unauthorized tones. It's the reason why a local office can leave their subscriber Touch-Tone circuits active, almost inviting you to use the Touch-Tone service. A few days after you use an unauthorized Touch-Tone service, the business office will call and inquire whether you'd like to pay for the service or have it disconnected. The very same central-office equipment that knows you're using Touch-Tone frequencies knows if you line is originating CCITT signals. THE RED BOX The Red Box was primarily used by the college crowd to avoid charges when many calls were made between two particular locations, say the college and a student's home. Unlike the somewhat complex cicuitry of a Blue Box, a Red Box was nothing more than a modified telephone; in some cases nothing more than a capacitator,a momentary switch, and a battery. As you recall from our discussion of the Blue Box, a telephone circuit is really established before the target phone ever rings, and the circuit is capable of carrying an AC signal in either direction. When the caller hears the ringing in his or her handset, nothing is happening at the receiving end because the ringing signal he hears is really a tone generator at his local telephone office. The targe (called) telephone actually gets 20 pulses-per-second ringing voltage when the person who dials hears nothing- in the "dead" spaces between hearing nothing and the ringing tone. When the called phone is answered and taken off the hook, the telephone compleats a local-office DC loop that is the signal to stop the ringing voltage. About three seconds later the Din a signal being sent all the way back to the caller's AMA machine that the called the telephone was answered. Keep that the three-second AMA delay in mind. (By now you should have a pretty good idea of what's coming!) Figure 3 shows the simplified functonal schematic of the telephone. Switch S1 is the hook switch. When S1 is open (on-hook) only the ringer circuit consisting of C1 and BELLI is connected across the line. Capacitator C1 really has no purpose in the ringing ciruit; it only serves to keep the DC from flowing through BELLI. When the local telephone office feeds a 20-pps ringing signal into the line it flows though c1 and a ringer coil in BELLI. A vibrating device attached to BELLI strikes a small ball- the ringing device. When the phone is answered by lifting the handset across from its cradle, switch s1 closes (goes off-hook) and connects the handset across the telephone line. since the handset's receiver and transmitter (microphone) are connected in series, a DC path is established fro one side of the line to the other- what is called completing a DC loop with the central office. The DC current flowing in the loop causes the central office to instantly stop the ringin signal. When the handset is replaced in its cradle, s1 is opened, the DC loop is broken, the circuit is clear, and a signal is sent to the originating telephon's AMA machine that the called party has disconnected. Now as we said earlier, the ciruit can actually carry AC before the DC loop is closed. The Red Box is simply a device that provides a telephone with a local battery so that the phone can generat and AC signal without having a DC connection to the phone line. The earliest of the Red Boxes was the surplus military field telephone, of which there were thousands upon thousands in the marketplace during the 1950's and 1960's. The field telephone was a portable telephone unit having a manual ringer worked by crank- just like the telephone Grandpa used on the farm -and two D-cells. A selector switch set up the unit so that it functioned as a standard telephone that could be connected to a combat switchboard, with the DC power supplied by the switchboard. but if a combat unit wasn't connected to a switchboard, and the Lieutenant yelled "Take a wire," the signalman threw a switch on his field telephone that switched in the local battaries. To prevent the possibility of having both ends of the circuit feeding battery current into the line in opposit polarity- therby resulting in silence -the output from the field telephone was running from its internal batters ws only the AC representing voice input, not modulated DC. Figure 4 is the functional simplified schematic for a field telephone (do not attempt fo build that ciruit). Momentary switch s4 is not part of the field telephone, it is added when the phone is converted to a Red Box; so for now, consider that S4 does not exist. Once again, S1 is the hook switch. When S2 is set to N (NORMAL) and S1 is closed, DC flows from line A through T1's secondary (S), through S2-a to S2-b,rimary (P), through the handset, through S2-c, to line B. There is a complete DC path across the line, and if the unit is connected across a conventional subscriber telephone line it will close the Dc loop from the local office. to use the field telephone as a Red Box, switch S2 is set to L (LOCAL). Switches S2-b and S2-c connect batteries B1 and B2 in series with the handset and the transformer's primary, which constitute an active, working telephone ciruit. Switch S2-a connects T2's secondary to one side of the telephone line through a non-polarized capacitator (C1), so that when hook-switch S1 is closed, T1's secondary cannot close the Dc loop. PRESS ONCE TO TALK The Red Box was used at the receiving end; let's assume it's the oldhomestead. The call was originated by Junior (or Sis) at their college 1000 miles from home. Joe gave the family one ring and hung up, which told them that he's calling. Pop set up the Red Box by setting S2 to LOCAL. Then Junior redialed the old homestead. Pop lifted the handset when the phone rang, which closed S1. Then Pop closed momentary-switch S4 for about a half-second, which caused the local telephone office to silence the ringing signal. When Pop release S4, the folks can talk to Junior without Junior getting charged because his AMA tape did not show his call was answered- the DC loop must be closed for at least three-seconds for the AMA tap to show Junior's call was answered. All the AMA tape showed is that Junior let phone at the old homstead ring for almost 30 minutes; a length of time that no Bell Operating Company is likely to believe twice! A modern Red Box is simply a conventional telephone that's been modified to emulate the vintage 1940 military field telephone. Aside from the fact that the operating companies can now nail every Red Box user because all modern billing equipment shows the AMA information concerning the length of time a caller let the target phon ring, it's use has often put severe psychological strain on the users. Does getting electronics mixed up with psychology sound strange? Well it isn't because it's what helped Ma Bel put an end to indiscriminate use of the Red Box. The heyday of the Red Box was the 1950's and 1960's. Mom and Pop were lucky to have finished high school, and almost without exception, both elementry and high schools taught honesty and ethics. Mom and Pop didn't have the chance to take college courses like Stealing 101 that masqueraded under quaint names such as Business Management, Marketing, o Arbitrage. When Junior tried to get the old folkes to use his "free telephone" they just wouldn't go along. So Junior installed the Red Box on his end. He gave one ring to notify the family to call him back. When Pop called Junior, it was Junior who was using the Red Box. Problem was, Junior didn't know that the AMA tapes for Mom and Pop's phone showed a 20- or 30-minute ringing. When Ma Bell's investigators showed up it was only then that the folks discovered their pride and joy had been taught to steal. There are nncering how many Red Boxes were in use, or how much money Ma Bell lost, but one thing is known: she had little difficulty in closing down Red Boxes in virtually all instances where the old folks were involved because Mom and Pop usually would not tolerate what to them was stealing. If you as a reader have any ideas about using a Red Box, bear in mind that the AMA (or its equivalent) will get you every time, even if you use a phone booth, because the record will show the number being called, and as with the Blue Box, the people will spill their guts to the cops.