Part 27 About Pots Modules - Tieline ViA User Manual

120 ViA User Manual v2.0
27 About POTS Modules
The ViA POTS G5 module is essentially the same as other G5 POTS modules in Genie and Merlin
codecs. It can be used in the codec to stream high quality audio over a POTS (PSTN) phone line.
The Tieline Music algorithm can deliver 15 kHz quality bi-directional audio at bit rates as low as
24kbps over a POTS connection.
Modem Negotiation and Line Quality
The codec can send and receive high-speed digital information over a standard POTS telephone line
via the modem in the ViA POTS module.
ViA POTS module modems initially attempt to establish a link at the lowest Maximum Bit rate
setting configured in the POTS Module settings. If the POTS line doesn't support a selected bit
rate, the modems will attempt to connect at the highest possible bit rate to suit the prevailing line
quality at each end of the link. The modem then performs a process called 'training', during which
the codecs at each end of the link analyze the line. The codecs will then 'renegotiate' the link
downwards to the highest possible bit rate where line quality is greater than 70%.
The ViA POTS module contains a SmartDAA™ (Smart Data Access Arrangement) line interface,
which isolates the modem from voltages on phone lines. It is important to select the correct country
in the codec from which you are dialing. This allows the SmartDAA to automatically adjust for
varying ring tones and line impedances in different countries.
Connecting to G3 Codecs using POTS
The codec will successfully connect to Tieline Commander G3 and i-Mix G3 codecs, as well as the
Genie and Merlin codec families over POTS. Tieline G3 codecs may use:
·
POTS modules (older superseded G3 codec version)
·
POTS G3 modules (current G3 codec version)
Connecting to POTS G3 Modules
POTS G3 modules operate in the same way as all G5 POTS modules (Genie, Merlin and ViA)
when connecting, e.g. they establish a link at the default bit rate of 28.8kbps and then
'renegotiate' the link downwards to the highest possible bit rate where line quality is greater than
70%.
Connecting to Legacy POTS Modules in G3 Codecs
These modules have slightly different characteristics when connecting. When dialing from a G5
POTS module to these older POTS modules the codecs will attempt to connect initially at
19.2kbps. If line quality is above 80% at this bit rate then the codec will 'retrain' the connection
up to a maximum of 28,800bps (depending on modem handshaking). The codec will then
renegotiate the link downwards to the highest possible bit rate where line quality is greater than
70%.
© Tieline Pty. Ltd. 2017