User`s manual

MediaPack
SIP User's Manual 330 Document #: LTRT-65408
15.2 Prerecorded Tones (PRT) File
The Call Progress Tones mechanism has several limitations, such as a limited number of
predefined tones and a limited number of frequency integrations in one tone. To work
around these limitations and provide tone generation capability that is more flexible, the
PRT file can be used. If a specific prerecorded tone exists in the PRT file, it takes
precedence over the same tone that exists in the CPT file and is played instead of it.
Note that the prerecorded tones are used only for generation of tones. Detection of tones is
performed according to the CPT file.
15.2.1 PRT File Format
The PRT dat file contains a set of prerecorded tones to be played by the MediaPack during
operation. Up to 40 tones (totaling approximately one minute) can be stored in a single file
in flash memory. The prerecorded tones (raw data PCM or L8 files) are prepared offline
using standard recording utilities (such as CoolEdit
TM
) and combined into a single file using
the TrunkPack Downloadable Conversion utility (refer to Section E.1.3 on page 366).
The raw data files must be recorded with the following characteristics:
 Coders: G.711 A-law, G.711 µ-law or Linear PCM
 Rate: 8 kHz
 Resolution: 8-bit
 Channels: mono
The generated PRT file can then be loaded to the MediaPack using the BootP/TFTP utility
(refer to Section 5.9.2.1 on page 203) or via the Embedded Web Server (Section 5.9.2 on
page 202).
The prerecorded tones are played repeatedly. This enables you to record only part of the
tone and play it for the full duration. For example, if a tone has a cadence of 2 seconds on
and 4 seconds off, the recorded file should contain only these 6 seconds. The PRT module
repeatedly plays this cadence for the configured duration. Similarly, a continuous tone can
be played by repeating only part of it.
Note: The maximum size of a PRT file that can be loaded to the gateway is
100 KB.