FLEX is a

communications protocol A communication protocol is a system of rules that allows two or more entities of a communications system to transmit information via any kind of variation of a physical quantity. The protocol defines the rules, syntax, semantics and synch ...

developed by

Motorola Motorola, Inc. () was an American multinational telecommunications company based in Schaumburg, Illinois, United States. After having lost $4.3 billion from 2007 to 2009, the company split into two independent public companies, Motorola ...

and used in many

pager A pager (also known as a beeper or bleeper) is a wireless telecommunications device that receives and displays alphanumeric or voice messages. One-way pagers can only receive messages, while response pagers and two-way pagers can also acknow ...

s. FLEX provides one-way communication only (from the provider to the pager device), but a related protocol called

ReFLEX In biology, a reflex, or reflex action, is an involuntary, unplanned sequence or action and nearly instantaneous response to a stimulus. Reflexes are found with varying levels of complexity in organisms with a nervous system. A reflex occurs ...

provides two-way messaging.

Protocol

Transmission Transmission may refer to: Medicine, science and technology * Power transmission ** Electric power transmission ** Propulsion transmission, technology allowing controlled application of power *** Automatic transmission *** Manual transmission ** ...

of message data occurs in one of four modes: 1600/2, 3200/2, 3200/4, or 6400/4. All modes use FSK

modulation In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the '' carrier signal'', with a separate signal called the ''modulation signal'' that typically contains informat ...

. At 1600/2 this is on a 2 level FSK signal transmitted at 1600 bits per second. At 3200/2, this is a 2 level FSK signal transmitted at 3200 bits per second. At 3200/4, this is a 4 level FSK signal transmitted at 1600 symbols per second. Each 4 level symbol represents two bits for a bit rate of 3200 bits per second. At 6400/4, this is a 4 level FSK signal transmitted at 3200 symbols per second or 6400 bits per second. Data is transmitted in a set of 128 frames that takes 4 minutes to complete. Each frame contains a sync followed by 11 data blocks. The data blocks contain 256, 512 or 1024 bits for 1600, 3200 or 6400

bits per second In telecommunications and computing, bit rate (bitrate or as a variable ''R'') is the number of bits that are conveyed or processed per unit of time. The bit rate is expressed in the unit bit per second (symbol: bit/s), often in conjunction ...

respectively. The standard has been designed to allow the pager's receiver to be turned off for a high percentage of the time and therefore save on

battery Battery most often refers to: * Electric battery, a device that provides electrical power * Battery (crime), a crime involving unlawful physical contact Battery may also refer to: Energy source *Automotive battery, a device to provide power t ...

usage.

Security

Transmitted data over FLEX is not encrypted. A BCH error correcting code is used to improve the integrity of the data, although this is not cryptographically secure. There have been reported instances of individuals actively listening to pager traffic (private investigators, news organizations, etc.).

Usage

The Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

the emergency services use the Flex-protocol in the nationwide P2000 network for pagers. The traffic on this network can be monitored online. In

South Australia South Australia (commonly abbreviated as SA) is a States and territories of Australia, state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest o ...

the State's SAGRN network for the Emergency Services paging system (CFS, SES, MFS and SAAS) is run on the FLEX 1600 protocol, and can be monitored online.

External links

FLEX: The New Edge For The Paging Industry

Design And Implementation Of A Practical FLEX Paging DecoderUS6396411B1: Reliable and fast frame synchronization scheme for flex paging protocol

References

{{Motorola Network protocols Motorola Radio paging

Protocol

Security

Usage

See also

External links

References