Digium TC400B, Руководство пользователя

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Chapter 1
Overview
The TC400 Series cards are a bundle of the half-length, low-profile
TC400P (PCI) or TCE400 (PCI-E) base card and the TC400M voice
processing module. The TC400 Series cards are designed to handle, in
dedicated DSP resources, the complex codec translations for highly
compressed audio as would otherwise be processed by Asterisk in
software.
Asterisk, in software and with Digium® G.729a licensing, is capable of
transforming the G.729a codec into other codecs for the purposes of call
origination or termination, bridging disparate calls, or VoIP to TDM
connectivity. These transformations in software are very expensive, in
terms of MIPS, and require a substantial amount of CPU time to
accomplish. A TC400 Series card not only relieves the CPU of this duty,
freeing it up to handle other tasks or to complete additional call
processing; but also provides Asterisk with the capability of bridging
G.723.1 compressed audio into other formats, a capability not previously
possible.
The TC400 Series cards decompress G.729a (8.0 Kbit) or G.723.1 (5.3
Kbit and 6.3 Kbit) into u-law or a-law; or, compress u-law or a-law into
G.729a (8.0 Kbit) or G.723.1 (5.3 Kbit and 6.3 Kbit). The TC400 Series
cards are rated to handle up to 120 bi-directional G.729a transformations
or 92 bi-directional G.723.1 transformations. The TC400 Series cards do
not require additional licensing fees for the use of these codecs nor do
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