Trackit Mk3 User Manual
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Appendix 5: Bluetooth Wireless
Introduction
Using a single plug- in Bluetoot h int erface m odule on t he Trackit Mk3, wireless connections can be
est ablished with it from any Bluetooth- enabled PC, Laptop or PDA. This allows t he Trackit Mk3 to
be cont rolled or m onit ored rem ot ely over a secure wireless link up t o a range of about 100m or
great er ( dependent on hardware and environm ent al factors).
Bluetooth primer
I t is not intended here t o provide a full introduction to Bluet oot h technology, how it works and how
to use it . There is a huge am ount of inform at ion elsewhere that is available for t his purpose. Nev-
ertheless, a short descript ion will be given t o ident ify som e of t he com m on t erm s that will be used
lat er in the docum ent .
The t erm "Bluet oot h" refers t o a worldwide st andard for the wireless exchange of dat a between two
devices.
I n order to exchange data, two Bluet ooth devices m ust est ablish a connect ion. Before a connection
is established, one device m ust request a connection with another. The second device accepts (or
rej ects) the connect ion.
The originat or of t he request is known as the client. The device that accept s (or rej ect s) t he re-
quest is known as the server. Many Bluetooth devices can act as bot h client and server.
A client Bluet oot h device runs a software program t hat request s a connect ion to anot her device as
part of its norm al operat ion. For exam ple, the program m ay request a connection to a rem ot e com -
put er, a printer, a m odem or a Trackit Mk3.
Becom ing a Bluet ooth client norm ally requires an action by t he device operator, such as an at t em pt
to browse a rem ote com put er, print a file, dial out on a m odem or connect t o a Trackit Mk3.
Every Bluetooth device t hat provides a service m ust be prepared to respond t o a connection re-
quest . Bluetoot h software is norm ally running in the background on t he server, ready t o respond t o
connection request s.
Specificat ion Summary
• The devices in a piconet shar e a com m on com m unicat ion dat a channel. The channel has a
tot al capacity of 1 m egabit per second (Mbps). Headers and handshaking inform at ion con-
sum e about 20 percent of this capacit y.
• I n t he Unit ed Stat es and Europe, the frequency range is 2,400 t o 2,483.5 MHz, wit h 79 1-
MHz radio frequency ( RF) channels.
• A dat a channel hops random ly 1,600 times per second between t he 79 RF channels.
• Bluet ooth can t ransm it up to 721 kilobits per second (Kbps) in one direction, with 57.6
Kbps in t he ot her. If the use calls for t he sam e speed in both directions, a link wit h 432.6-
Kbps capacity in each direct ion can be m ade.
• Each channel is divided into t im e slot s 625 m icroseconds long.
• A piconet has a m aster and up t o seven slaves.
• Packet s can be up t o five t im e slots wide.
• Dat a in a packet can be up t o 2,745 bit s in lengt h.
• There are currently t wo types of data t ransfer between devices: SCO ( synchr onous connec-
tion oriented for voice and audio) and ACL (asynchronous connect ionless) .
• I n a piconet , there can be up t o t hree SCO links of 64,000 bit s per second each.
• Masters can support up t o t hree SCO links wit h one, t wo or t hree slaves.
• Slot s not reserved for SCO links can be used for ACL links.
• One m ast er and slave can have a single ACL link.
• ACL is eit her point - t o-point ( m aster t o one slave) or broadcast t o all t he slaves.
• ACL slaves can only transm it when requested by the m aster.
• A Class 1 device has a m axim um output power of 100m W (20dBm ) and has a range of
about 100m .
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