Evidenced by the dispatcher reading the list of units assigned to Division 3, the CAD system was working properly at dispatch positions. At least some field units experienced problems. Possible causes of problems with data terminals in vehicles may have included: The radio backbone may have been overloaded because of the unusually high volume of requests for information from field units. Radio networks carrying data traffic have a finite data throughput capacity and can be overloaded. Even a well-designed system has some capacity limit. A bottleneck someplace in the network between the radio modem and the CAD system back end may have been overloaded by unusually heavy data traffic. Data terminals use a robust error correction protocol. A failure of some part of the radio backbone may have caused reduced radio signals in field units. The bit errors caused by weaker signals may have caused a corresponding increase in resending of data packets. Resent packets reduce overall data throughput. The attack placed an unusually heavy load on voice system channels. Interference problems caused by interactions between voice radio channel transmitters and data radio system elements may have caused an increase in bit errors, slowing data throughput. Data terminals are partly purchased and installed to reduce load on dispatch staff and to reduce traffic on voice channels. When they work properly, they have a significant operational benefit. A data outage during an occurrence of high call traffic can quickly overrun dispatch and voice channel capacity in cases where a routine level of calls for service requires both data terminals and voice channels. New York City Council investigation New York City Council member Eric Gioia introduced a measure to have the Council investigate the issue of FDNY radio problems. See also Collapse of the World Trade Center References Notes Further reading Current Status, Knowledge Gaps, and Research Needs Pertaining to Firefighter Radio Communication Systems,, National Institute for Occupational Safety and Health, September 2003. Dwyer, Jim and Flynn, Kevin. 102 Minutes: The Untold Story of the Fight to Survive Inside the Twin Towers (New York: Times Books, 2004) Joyce, John (FDNY Capt.) and Bowen, Bill, Radio Silence F.D.N.Y. – The Betrayal of New York's Bravest, (Chesapeak Books, 2004) Krenning, Teresa A, "Incident management information exchange among operations centers of public safety agencies", 2000, (College Station, Texas: Texas Transportation Institute, 2000) p. 163–187. Special Report: Improving Firefighter Communications, USFA-TR-099/January 1999, (Emmitsburg, Maryland: U.S. Fire