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76-535: STU-III are no longer in service with the U.S. Government, with the last cryptographic keys for the units expiring on December 31, 2009. It has been replaced by the STE ( Secure Terminal Equipment ) and other equipment using the more modern Secure Communications Interoperability Protocol (SCIP). Most STU-III units were built for use with what NSA calls Type 1 encryption . This allows them to protect conversations at all security classification levels up to Top Secret , with

152-509: A "seed key" installed. This key is shipped from NSA by registered mail or Defense Courier Service . Once the STU-III has its seed key, the user calls a toll-free number at NSA to have the seed key converted into an operational key. A list of compromised keys is downloaded to the STU-III at this time. The operational key is supposed to be renewed at least once a year. The operational key is then split into two components, one of which replaces

228-546: A built-in RS-232 port. STE is intended to replace the older STU-III office system and the KY-68 tactical system. STE sets are backwards compatible with STU-III phones, but not with KY-68 sets. STE sets look like ordinary high-end office desk telephones and can place unsecured calls to anywhere on the public switched telephone network (PSTN), as well as secured calls on it via the phone's backwards compatible STU-III mode. There

304-526: A citywide channel. There were also five simplex channels in FDNY radios. Observation shows, back in 2001, that the citywide EMS channel was voting more frequently than normal, signals were noisy, interfering signals were present, and that some receiver sites had equalization differences. Some transmissions had choppy audio possibly representative of interference from FSK paging or intermittent microwave radio paths to one or more receiver sites. For example, if

380-467: A firefighter who has been injured or needs help. It also automatically displays the unit ID at the dispatch console. In most systems, it also saves dispatch personnel from typing the unit ID. They press one key and the calling unit's ID is inserted into the current CAD screen or command line. Recordings show radios were programmed to send unit ID on tactical channels. Radios accept unit ID on a per-channel basis. When mobile or hand-held radios are programmed,

456-651: A hijack situation, had no access to decision makers, and had none of the information available to senior FAA officials by that time. We found no evidence that, at this critical time, during the morning of September 11, NORAD’s top commanders, in Florida or Cheyenne Mountain Complex , ever coordinated with their counterparts at FAA headquarters to improve situational awareness and organize a common response. Lower-level officials improvised—the FAA’s Boston Center bypassing

532-534: A major role during and after the attack, starting with hijacked passengers who called family or notified the authorities about what was happening. Passengers and crew who made calls include: Sandra Bradshaw , Todd Beamer , Tom Burnett , Mark Bingham , Peter Hanson, Jeremy Glick , Barbara Olson , Renee May, Madeline Amy Sweeney , Betty Ong , Robert Fangman, Brian David Sweeney , and Ed Felt . Passengers and crew aboard United Airlines Flight 93 were able to assess their situation based on these conversations and plan

608-424: A microwave radio path fails for half-second intervals, the voting comparator may vote out that receiver site until silence is detected. This can cause dropped syllables in the voted audio. Some transmissions were noisy, although transactions show the dispatcher was understanding radio traffic in spite of audio drop-outs in almost every case. The Port Authority radio repeater , intended to allow communications inside

684-467: A problem. Even if a cache of radios were brought to the scene to hand out, the scale of this incident would be likely to overrun the number of radios in the cache. NIST concluded, at the beginning of the incident, there was an approximate factor of five (peak) increase in radio communications traffic over a normal level. After the initial peak, radio traffic through the incident followed an approximate factor of three steady increase. FDNY recordings suggest

760-562: A revolt that resulted in the aircraft crashing before reaching the hijackers’ intended target. According to the commission staff: "Their actions saved the lives of countless others, and may have saved either the U.S. Capitol or the White House from destruction." According to the 9/11 Commission Report, 13 passengers from Flight 93 made a total of over 30 calls to both family and emergency personnel (twenty-two confirmed air phone calls, two confirmed cell phone and eight not specified in

836-567: A thousand police, fire, and emergency medical services (EMS) staff arrived at the scene. At some point during a large incident, any agency will reach a point where they find their resources overrun by needs. For example, the Port Authority Police could not schedule staff as if a September 11 attack would occur every shift. There is always a balance struck between readiness and costs. There is conflicting data but some sources suggest there may have been 2,000 to 3,000 workers involved in

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912-538: A typical STE terminal cost about $ 3,100, not including the crypto card. Communication during the September 11 attacks Communication problems and successes played an important role during the September 11 attacks in 2001 and their aftermath. Systems were variously destroyed or overwhelmed by loads greater than they were designed to carry, or failed to operate as intended or desired. The organizers of

988-480: A user on the channel, the user steps through every channel selection on the remote, trying each one. The recording contains the tone remote control console stepping through all of its eight function tones. Someone says, "... the wireline isn't working", over the Port Authority channel. Something that looks like a Motorola T-1380-series remote is shown in the documentary. The fact that users pressing buttons on

1064-678: Is a PC Card slot in the STE that allows a Fortezza Plus ( KOV-14 ) Crypto Card or KSV-21 Enhanced Crypto Card to be inserted. When an NSA configured Crypto Card is present, secure calls can be placed to other STE phones. STE phones are "releasable" (unlike STU-III sets). All cryptographic algorithms are in the crypto card. Newer STE sets can communicate with systems that use the Secure Communications Interoperability Protocol (SCIP) (formerly Future Narrowband Digital Terminal (FNBDT)). There are upgrade kits available for older units. As of 2007,

1140-579: Is also considerably higher (STU-III: up to 9 kbit/s; STE: up to 128 kbit/s). Lastly, an STE unit is backward compatible with an STU-III unit when both units are connected to the PSTN. The heart of an STE unit is the Fortezza Plus ( KOV-14 ) Crypto Card, which is a PCMCIA card . It contains both the cryptographic algorithms as well as the key(s) used for encryption. Cryptographic algorithms include BATON, FIREFLY, and SDNS signature algorithm. When

1216-417: Is likely a source of continued misunderstanding; particularly when these same radios were operating at higher floors, in closer proximity to, and in direct line-of-sight of digital cellular repeaters. Those repeaters were likely operating at unlicensed power levels, which was a common practice of cellular providers at the time, and continues to this day. Footage reveals intelligible recovered audio coming out of

1292-531: The 140 West Street exchange being shut for days. Capacity between Brooklyn and Manhattan was also diminished by cut trunk cables. Following the attacks, the issues with the cell network weren't resolved until 36 cellular COWs (cell towers on wheels) were deployed by September 14, 2001, in Lower Manhattan to support the U.S. Federal Emergency Management Agency (FEMA) and provide critical phone service to rescue and recovery workers. Since three of

1368-465: The STU-II (1975). The STU-II had some 10,000 users. These, in turn, replaced less secure voice scramblers . Unlike earlier systems, the STU-III's encryption electronics are completely contained in the desk set. Further, the reduced bandwidth required by a STU-III permitted it to be used for encrypted voice communications even over limited conduits such as the commercial maritime communication satellites of

1444-576: The photography capabilities that became widespread by the mid-2000s. After the attack, the cell phone networks of New York City and the Tri-State area were rapidly overloaded (a mass call event ) as traffic doubled over normal levels. Cell phone traffic also overloaded across the East Coast, leading to crashes of the cell phone network. Verizon 's downtown wire phone service was interrupted for days and weeks because of cut subscriber cables, and to

1520-595: The Crypto Card is removed from the STE unit, neither the phone or the card is considered classified. BATON is a block cipher developed by the NSA with a block size of 128 bits and key size of 320 bits. FIREFLY , on the other hand, is a key distribution protocol developed by the NSA. The FIREFLY protocol uses public key cryptography to exchange keys between two participants of a secured call. Both STU-III and STE are built on technologies that are proprietary, and details of

1596-603: The FDNY fire units but generally cover shorter distances over open terrain. The Commission report did not cite any technical flaws with the NYPD radio system. PAPD has systems described as low-power UHF . The Commission report says the systems were specific to a single site with the exception of one channel which was Port-Authority-wide. It's unclear whether the PAPD systems were interstitial and limited to 2 watts output, used normal local-control channels but were limited in power output by

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1672-497: The North Tower lobby command post to communicate without using a hand-held radio. In a review of the logging recorder track of the Port Authority repeater, someone arrived early during the incident and began to establish a command post. From the command post in the lobby of the North Tower (1 World Trade Center), the user can be heard trying to transmit using a remote control unit. After several failed attempts to communicate with

1748-586: The Port Authority UHF radios were normally used at incidents inside the World Trade Center. The interviewee said in normal, day-to-day calls, the WTC staff handed Port Authority UHF radios to firefighters on their arrival and that these radios, "worked all over." This implies, but does not prove, that it was common knowledge among department members that FDNY radios had coverage problems inside

1824-492: The September 11 attacks served a vital role in coordinating rescue efforts by New York Police Department , New York Fire Department, Port Authority Police Department , and emergency medical services . While radio communications were modified to address problems discovered after the 1993 World Trade Center bombing , investigations into the radio communications during the September 11 attacks discovered that communication systems and protocols that distinguished each department

1900-492: The September 11 attacks . STE succeeded STU-III in the 1990s. Similar to STU-III, an STE unit physically resembles an ordinary telephone. Besides connecting to a regular wall phone jack ( Public Switched Telephone Network ), the STE was originally designed to be connected to Integrated Services Digital Network (ISDN) lines. As a result, in addition to having secured voice conversations, users can also use an STE unit for classified data and fax transmissions. Transfer rate of an STE

1976-404: The September 11, 2001 terrorist attacks apparently planned and coordinated their mission in face to face meetings and used little or no electronic communication. This " radio silence " made their plan more difficult to detect. According to 9/11 Commission staff statement No. 17 there were several communications failures at the federal government level during and after the 9/11 attacks. Perhaps

2052-481: The United States are interested in STU-III, STE, and other secured voice technologies developed by the NSA. To date, there has not been any reported cryptanalysis on the encryption algorithms used by the STU-III and STE. Any breaks in these algorithms could jeopardize national security . Information about STU-III is very limited despite the fact that it is out of production. Because of the sensitive nature of

2128-514: The World Trade Center to remain in place and wait for instruction from firefighters and police officers. This was the plan for managing a fire incident in the building and the 9-1-1 center staff were following the plan. This was partly countered by public safety workers going floor-by-floor and telling people to evacuate. The 9/11 Commission report suggests people in the NYPD 9-1-1 center and New York City Fire Department (FDNY) dispatch would benefit from better situation awareness. The Commission described

2204-490: The air. Unlike most other major New York television stations, WCBS-TV maintained a full-powered backup transmitter at the Empire State Building after moving its main transmitter to the North Tower of the World Trade Center. The station was also simulcasted nationally on Viacom (which at the time owned CBS) cable network VH1 that day. In the immediate aftermath of the attacks, the station lent transmission time to

2280-462: The best of what was available to them. Typical of any large fire, many 9-1-1 calls with conflicting information were received beginning at 8:46 am. In addition to reports that a plane had hit the World Trade Center, the EMS computer-aided dispatch (CAD) log shows reports of a helicopter crash, explosions, and a building fire. Throughout the incident, people at different locations had very different views of

2356-449: The buildings. The 9-11 Commission uses the phrase, "performed poorly" to describe FDNY radios during the incident. Oral history files show that at least four channels were employed at WTC: One officer said a channel named Command 3 was used for the North Tower. To those unfamiliar with the details of the FDNY system, it is unclear whether the interviewee meant Tactical 3 or a fifth channel. FDNY personnel are seen using radios during

STU-III - Misplaced Pages Continue

2432-407: The call being placed. Each unit first makes sure that the other is not using a revoked key and if one has a more up-to-date key revocation list, it transmits it to the other. Presumably the revocation lists are protected by a digital signature generated by NSA. While there have been no reports of STU-III encryption being broken, there have been claims that foreign intelligence services can recognize

2508-412: The call centers as not "fully integrated" with line personnel at the WTC. The report suggests the NYPD 9-1-1 center and FDNY dispatch were overrun by call volumes that had never been seen before. Adding to the confusion, radio coverage problems, radio traffic blocking, and building system problems occurred inside the burning towers. The facts show that much of the equipment worked as designed and users made

2584-502: The call. According to the staff report: Operators worked feverishly to include the FAA in this teleconference , but they had equipment problems and difficulty finding secure phone numbers. NORAD asked three times before 10:03 to confirm the presence of FAA on the conference, to provide an update on hijackings. The FAA did not join the call until 10:17. The FAA representative who joined the call had no familiarity with or responsibility for

2660-494: The chain of command to contact NEADS . But the highest level Defense Department officials relied on the NMCC’s Air Threat Conference, in which FAA did not meaningfully participate. After the 1993 World Trade Center bombing , radio repeaters for New York City Fire Department communication were installed in the tower complex. Because they were unaware that several controls needed to be operated to fully activate

2736-413: The channels were busy. In some cases, two or more conversations were taking place over a single radio channel at the same time. Users on Tactical 1 may have been close enough to one another to communicate because signals in proximity to each other would overpower weaker signals. At any incident of this size, there is likely to be some overlapping radio traffic. In the same way that large incidents exhaust all

2812-408: The city. The documentary film gives different information, with a Fire Department member from Engine 7/Ladder 1 claiming that the aircraft's impact caused the system to fail. Evidence suggests the remote control console in the lobby command was not working but the repeater was. The radio repeater was located in 5 World Trade Center. A remote control console was connected to the repeater allowing staff at

2888-681: The cryptographic algorithms (BATON and FIREFLY) are classified. Although the secrecy of the algorithms does not make the device less secure, it does limit the usage to within the U.S. government and its allies. Within the Department of Defense, Voice over IP (VoIP) has slowly emerged as an alternative solution to STU-III and STE. The high bandwidth of IP networks makes VoIP attractive because it results in voice quality superior to STU-III and STE. To secure VoIP calls, VoIP phones are connected to classified IP networks (e.g. Secret Internet Protocol Router Network – SIPRNET ). Both allies and adversaries of

2964-535: The day. The STU-III is no longer in use, having been replaced by the STE ( Secure Terminal Equipment ) or OMNI , more modern, all digital systems that overcome many of the STU-III's problems, including the 15 second delay. Operational difficulties in using STU-III phones hindered coordination between the Federal Aviation Administration and NORAD during the September 11, 2001 attacks on New York and Washington. See Communication during

3040-406: The dispatch personnel were overloaded: both fire and EMS dispatch were often delayed in responding to radio calls. Many 9-1-1 telephone calls to dispatch were disconnected or routed to "all circuits are busy now", intercept recordings. NIST calculated that about one third of radio messages transmitted during the surge of communications were incomplete or unintelligible. Documentary footage suggests

3116-585: The documentary ) was reviewed. It captured audio from hand-held radios in use at the incident and showed users communicating over radios from the lobby command post in the North Tower. 26 Red Book audio CDs of New York City Fire Department radio transmissions, covering the incident's initial dispatch and the tower failures, were reviewed. These CDs were digitized versions of audio from the Fire Department's logging recorders. In addition, text on an oral history CD with transcripts of fire personnel debriefed on

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3192-404: The documentary appeared to work properly even though several other hand-held radios were transmitting only feet away. This is a hostile environment and suggests the hand-held equipment used by FDNY had good quality receivers, though in this case, the suggestion is incorrect. Second-hand observation is hardly the proper way to 'test' radio receivers or to distinguish 'good quality' from 'bad' and this

3268-618: The documentary footage of the WTC lobby area. Analysis of these scenes showed the radios all appeared to be receiving properly. Oral history files confirm radio communications were at least partly functional. A problem that shows up in these types of incidents is that receivers in hand-held radios are subjected to signal levels that are likely to overload the receiver. Several radios may be transmitting within feet of one another on different channels. If overloading occurs, only very strong signals can be received while weaker signals disappear and are not received. The hand held radio receivers shown in

3344-458: The firefighting vehicles and staff, the radio channel resources may become taxed to their limits. NIST says about one third of the fire department radio transmissions were not complete or not understandable. Some radio users had selected the wrong channels. For example, on the Repeater 7 channel, a unit was heard to call Manhattan dispatch and Citywide . Although the circumstances that led to

3420-447: The first (South) tower collapsed. There was little communication between New York City Police Department and fire department commands even though an Office of Emergency Management (OEM) had been created in 1996 in part to provide such coordination. A primary reason for OEM's inability to coordinate communications and information-sharing in the early hours of the WTC response was the loss of its emergency operations center, located on

3496-569: The frequency coordinator, or used leaky cable systems which were solely intended to work inside the Port Authority buildings. The report says there were 7, site-specific Port Authority Police channels. In 2001, officers at one site could not, (in all cases), carry their radios to another site and use them. Not all radios had all channels. Recordings of Citywide, Brooklyn, and Manhattan channels for Fire and Citywide, Brooklyn, and Manhattan channels for Emergency medical services were reviewed. Systems generally performed well. The audio coupling point for

3572-402: The hijacked aircraft struck the World Trade Center, people inside the towers made calls to family and loved ones; for the victims, this was their last communication. Other callers directed their pleas for help to 9-1-1 . Over nine hours of the 9-1-1 calls were eventually released after petitioning by The New York Times and families of the WTC victims. In 2001, U.S. cell phones did not yet have

3648-430: The incident because the primary van was out-of-service. The backup van was destroyed and audio recordings of tactical channels used at the incident site were lost. One annoyance with the fire systems was the presence of unit ID data bursts. These constant squawks, heard at the end of transmissions, are decoded at dispatch to identify the calling radio. The annoyance of the data bursts is a trade-off that could help find

3724-405: The incident were reviewed. In 2001, the NYPD used Ultra High Frequency (UHF) radios and divided the city into 35 radio zones. Most hand-held radios had at least 20 channels: while not all officers had all channels, all officers had the ability to communicate citywide. As a characteristic of physics, UHF signals penetrate buildings better than lower Very High Frequency (VHF) frequencies used by

3800-504: The information on the KSD-64A, at which point it becomes a Crypto Ignition Key or CIK. When the CIK is removed from the STU-III telephone neither unit is considered classified. Only when the CIK is inserted into the STU-III on which it was created can classified information be received and sent. When a call "goes secure", the two STU-III's create a unique key that will be used to encrypt just

3876-528: The last image received from the WTC mast; the image (a remote-camera shot of the burning towers), viewable across North America (as WPIX is available on cable TV in many areas), remained on the screen for much of the day until WPIX was able to set up alternate transmission facilities. It shows the WTC at the moment power cut off to the WPIX transmitter, prior to the towers' collapse. During the September 11 attacks, WCBS-TV channel 2 and WXTV-TV channel 41 stayed on

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3952-501: The lines on which STU-IIIs are installed and that un-encrypted calls on these lines, particularly what was said while waiting for the "go secure" command to complete, have provided valuable information. Hundreds of thousands of STU-III sets were produced and many were still in use as of 2004. STU-III replaced earlier voice encryption devices, including the KY-3 (1960s), the STU-I (1970) and

4028-471: The logging recorder on Manhattan Fire made the dispatcher's voice difficult to hear. An anonymous fire dispatcher who identifies as Dispatcher 416 is noteworthy. The Commission report says that, in 2001, FDNY used a system with 5 repeater channels: one for each of the boroughs of Manhattan, Brooklyn, Queens, with the Bronx and Staten Island sharing a single frequency using different Private Line (PL) tones, and

4104-533: The major television broadcast network owned-and-operated stations had their transmission towers atop the North Tower (One World Trade Center), coverage was limited after the collapse of the tower. The FM transmitter of National Public Radio station WNYC was also destroyed in the collapse of the North Tower and its offices evacuated. For an interim period, it continued broadcasting on its AM frequency and used NPR's New York offices to produce its programming. The satellite feed of one television station, WPIX , froze on

4180-593: The maximum level permitted on a call being the lower clearance level of the two persons talking. At the height of the Commercial COMSEC Endorsement Program, Type 2 , 3 , and 4 STU-IIIs were manufactured, but they saw little commercial success. Two major factors in the STU-III's success were the Electronic Key Management System (EKMS) and the use of a removable memory module in a plastic package in

4256-555: The most serious occurred in an "Air Threat Conference Call" initiated by the National Military Command Center (NMCC) after two planes had crashed into the World Trade Center , but shortly before The Pentagon was hit. The participants were unable to include the Federal Aviation Administration (FAA) air traffic control command center, which had the most information about the hijackings, in

4332-516: The other stations who had lost their transmitters, until they found suitable backup equipment and locations. The Emergency Alert System was never activated in the terrorist attacks, as the extensive media coverage made it unnecessary. AT&T eliminated any costs for domestic calls originating from the New York City area (phones using area codes 212 , 718 , 917 , 646 , and 347 ) in the days following 9/11. Radio communications during

4408-428: The radios and shows radio users communicating with others. This may not have been true of the entire WTC complex but was true of radio users in the crowded lobby. Analysis of the 26 FDNY audio CDs showed the radios seemed to transmit into the radio systems okay. Radios calling dispatch got through. Calling units were intelligible. Users spoke with dispatchers. Dispatchers answered in ways that suggest they understood what

4484-496: The receive audio on the Port Authority Repeater 7 system. An ambulance being dispatched by the outside (non-FDNY) agency is heard. This may be what the FDNY had described as interference caused when the repeater was left enabled at all times. The distant user appears to be repeated through the system, (possibly on the same CTCSS tone as was configured in Repeater 7). This appears to be a distant co-channel user on

4560-541: The receivers in the system and therefore would not be a detectable problem when listening to the recordings. At the same time those recordings were made, the cellular system was operating at or near full-capacity, meaning every cellular repeater was transmitting. The dense RF interference environment created in NYC that day was essentially a 'perfect storm'; one in which a radio designed 25 years prior could not possibly contend with. In some scenes, captured documentary audio showed

4636-489: The remote control can clearly be heard on the logging recorder shows the transmit audio path was working. The recording does not reveal whether or not the console function tones were keying the transmitter. Some users in the North Tower lobby interpreted the remote control unit not working as a failure of the entire channel. Other fire units, not knowing the channel had failed, arrived and began using it successfully. The recordings show at least some units were successfully using

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4712-484: The repeater system, fire chiefs at their command post in the lobby of the North Tower thought the repeater was not functioning and did not use it, though it did work and was used by some firefighters. When police officials concluded the twin towers were in danger of collapsing and ordered police to leave the complex, fire officials were not notified. Fire officials on the scene were not monitoring broadcast news reports and did not immediately understand what had happened when

4788-531: The repeater to communicate inside the South Tower until the moment it collapsed. The Commission report says the North Tower lobby command may not have worked because of a technical problem, the volume control turned all the way down, or because a button that must be pressed to enable it had not been pushed. On the audio track, an outside agency, possibly in New Jersey and using a repeater, comes through

4864-411: The report). Brenda Raney, Verizon Wireless spokesperson, said that Flight 93 was supported by several cell sites. There were reportedly three phone calls from Flight 11 , five from Flight 175 , and three calls from Flight 77 . Two calls from these flights were recorded, placed by flight attendants: Betty Ong on Flight 11 and CeeCee Lyles on Flight 93. Alexa Graf, an AT&T spokesperson, said it

4940-557: The rescue operation. It would be rare for most agencies to see an event where there were that many people to be rescued. There is some level of confusion present in any large incident. The National Institute of Standards and Technology (NIST) asserts commanders did not have adequate information and interagency information sharing was inadequate. For example, on September 11, persons in the New York City Police Department (NYPD) 9-1-1 center told callers from

5016-400: The same input frequency as Repeater 7. It's possible that by the random button pressing, a user sent a function tone that temporarily put the base station in monitor and that's what caused the outside agency's traffic to be heard. This is unlikely because subsequent transmit function tones should have toggled the receiver from monitor back to CTCSS-enabled. An oral history interview revealed

5092-501: The shape of a house key, called a KSD-64A . The EKMS is believed to be one of the first widespread applications of asymmetric cryptography . It greatly reduced the complex logistics and bookkeeping associated with ensuring each encryption device has the right keys and that all keying material is protected and accounted for. The KSD-64A contains a 64 kbit EEPROM chip that can be used to store various types of keying and other information. A new (or zeroized ) STU-III must first have

5168-702: The situation. After the collapse of the first tower, many firefighters in the remaining tower had no idea the first tower had fallen. A factor in radio communications problems included the fact that off-duty personnel self-dispatched to the incident scene. Some off-duty staff went into the towers without radios. According to the Commission report and news coverage, this was true of NYPD, Port Authority Police Department (PAPD), and FDNY personnel. Regardless of any radio coverage problems, these persons could not be commanded or informed by radio. In any incident of this scale, self-dispatched staff without radios would likely be

5244-614: The subject, there are few relevant documents available. The majority of the information available originates from the manufacturers (e.g. L-3 Communications) of STU-III and STE. Secure Terminal Equipment Secure Terminal Equipment ( STE ) is the U.S. government's current (as of 2008 ), encrypted telephone communications system for wired or "landline" communications. STE is designed to use ISDN telephone lines which offer higher speeds of up to 128 kbit/s and are all digital. The greater bandwidth allows higher quality voice and can also be utilized for data and fax transmission through

5320-407: The tactical channels were also overloaded; some footage captured audio of two or three conversations occurring simultaneously on a particular channel. In this study of WTC incident communications, radio systems used at the site had problems but were generally effective in that users were able to communicate with one another. A 2002 video documentary 9/11 by Gedeon and Jules Naudet, (referred to as

5396-515: The towers, did not appear to work as intended on September 11. The system, also called Port Authority Channel 30 , was installed at Port Authority police desk in WTC 5 in 1994 after the 1993 World Trade Center attack. News accounts said the system had been turned off for unspecified technical reasons. The Commission report said it was customary to turn the system off because it somehow caused interference to radios in use at fire operations in other parts of

5472-485: The twenty third floor of 7 World Trade Center , which had been evacuated after debris from the main tower's collapse struck the building. This ignited several fires that caused it to collapse at 5 pm later that day. Emergency relief efforts in both Lower Manhattan and at the Pentagon were augmented by volunteer amateur radio operators in the weeks after the attacks. Cell phones and in-plane credit card phones played

5548-405: The user selecting the wrong channel are not known, this can occur when the user is trapped in darkness or smoke and cannot see the radio. Users will typically try to count steps in a rotary switch channel selector starting from one end of the switch's travel. A communications van operated by FDNY responded to the incident. Its radio identifier was, "Field Comm." A backup van was in use on the day of

5624-517: Was almost a fluke that the calls reached their destinations. Marvin Sirbu, professor of Engineering and Public Policy at Carnegie Mellon University said on September 14, 2001, that "The fact of the matter is that cell phones can work in almost all phases of a commercial flight." Other industry experts said that it is possible to use cell phones with varying degrees of success during the ascent and descent of commercial airline flights. After each of

5700-476: Was hampered by the lack of interoperability, damaged or failed network infrastructure during the attack, and overwhelmed by simultaneous communication between superiors and subordinates. A rough time line of the incident could include: The scale of the incident was described in the National Commission report on the attacks as unprecedented . In roughly seventeen minutes from 8:46 to 9:03 am, over

5776-507: Was said. There were no noisy or truncated transmissions heard on any channel, (the equivalent of a dropped cellular call). This suggests the Fire Department's radio backbone is soundly designed and working properly. It is possible that system coverage problems are present; problems that could have been mitigated had the Command Post radio (with greater transmit power) been used. It is also likely that some transmissions did not reach any of

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