CMX808A
Family Radio CTCSS ‘Type 2’
Encoder and Decoder
D/808A/5 March 1999
1.0 Features
• Unique CTCSS ‘Type 2’ Operation
• Fast Decode on all Tones (140ms)
• Tones from 60Hz to 251Hz
• Tone Cloning
• Low Power Operation (1.3mA at 3.0V)
Provisional Issue
• High Performance Encode/Decode
• Flexible Multiple Decode Options
• Sub-Audio Tone Rejection Filter
• 48 Programmable CTCSS Tones
• Compact 20-pin TSSOP Package
Applications
• Family Radio Service
(FRS) Handportables
• Amateur Radio
Equipment
• General Mobile Radio
Service (GMRS)
• Short Range
Business Radio
1.1 Brief Description
This device is a unique product for the designer of family radio transceivers. Offering leading edge
performance while also being highly cost effective. The device is simple to interface to a host of µControllers
via the serial programming interface. A full range of 48 tones can be generated and detected by the device.
The decode time has been vastly improved from that offered by other solutions. Fast response and de-
response gives the user of a family radio transceiver faster switching times and a reduction in the annoying
squelch tail often found in CTCSS based systems. The device has very low power consumption operating at
a minimum of 3.0V.
A unique feature of the device is its ability to look for 7 different CTCSS codes simultaneously. This allows
FRS designers to offer equipment which can look for personal, family or open channel codes at the same time.
For example a soccer team coach can call each of the 11 players individually or the team as a group. Codes
can be used as Paging codes, open chat mode codes as well as personal and family codes. These features
allow FRS designers to differentiate their products from that of the competition in unique ways to gain market
share in this highly competitive application. The CMX808A opens the way to rapid development of new family
radio applications.
© 1999 Consumer Microcircuits Limited