CPT
Detector/Generator
by DNA Enterprises, Inc.

Software Overview

DNA Enterprises' Call Progress Tone (CPT) Detection/Generation package implements a multi-channel 
CPT generator and receiver. The number of channels is configurable at compile time and each 
transmit channel is individually configurable. This package is developed for the TMS320C3x digital 
signal processor and CPT signals are generated and detected as specified in Bellcore LSSGR Section 
6.4.3.
The CPT package detects the following tones: call interrupt, high tone, dial tone, audible ringing, 
and low tone.
The software's modular design separates signal detection and generation issues from data I/O and 
command I/O issues. This allows the CPT software to "bolt" into custom hardware platforms. Data 
memory requirements for this algorithm are based on the number of channels configured. Less data 
memory is used if fewer channels are required.

Features and Benefits

•	Simultaneously generates and detects CPT on up to 24 channels 
•	Modular design allows custom I/O development
•	Transmits/receives tones according to Bellcore LSSGR Section 6.4.3
•	Number of channels is configurable
•	Supports stack or register parameter passing

Processor and System Requirements

Target processor:
TMS320C3x DSP
Algorithm category:
Telecommunications
Program memory usage:
635 words
Data memory usage:
8550 words (based on 24 channels)
Transmitter processor loading:
0.16 MIPS (per channel)
Receiver processor loading: 
0.46 MIPS (per channel)
Data coding format:
13-bit linear PCM at 8 kHz

Algorithm Verification

DNA Enterprises' CPT algorithm was validated on a third-party PC plug-in board using a 33-MHz 
TMS320C3x according to Bellcore LSSGR Section 6.4.3. The following receiver tests were included in 
the test suite:
•	CPT tone detection
•	CPT tone rejection due to low levels
•	CPT tone detection with ±10% signal-duration variations
•	Disturbing tone rejection at low levels 
•	Low- and high-frequency tone rejection at high levels

Availability

•	Available now on the TMS320C3x DSP
•	Licensable in object or source-code format

DNA Enterprises offers consulting services to tailor the CPT Detector/Generator software package to 
your specific needs.  This includes porting the algorithm to another Texas Instruments DSP.

Company Background and Contact Information

DNA Enterprises Inc. specializes in telecommunication and real-time multiprocessor embedded 
systems. We provide turnkey design and development, offering software, hardware, and digital signal 
processing expertise for all project phases.

Contact:	Mr. Brian Berger
		269 West Renner Parkway
		Richardson, Texas  75080
		(214) 644-3301
		Fax: (214) 644-6338
		e-mail: info@dna.metronet.com