Section 8: POTS Operation and Usage Tips
T
ieline
Page
64
T E C H N O L O G Y
8.2.
Modem Negotiation and Line Quality for POTS Mode
The
i
-
Mix
G
3
sends and receives high-speed digital information over a standard
telephone line via an internal modem or a POTS module. A
COMMANDER
G
3
codec
uses POTS modules only. The POTS modems communicate over the
phone line to establish the best possible configurations for data transmission and
to achieve the highest reliable data rate. This also corresponds to best possible
audio quality.
Upon connection the modems initially establish a link at the default bit rate of
19,200 bps. The modems then perform a process called ‘training’ in which they
analyze the line and compensate for frequency and phase response. This process
also cancels out any echo that may be present.
The training process continues until the modems establish the highest reliable
speed for data transfer using a process of ‘negotiation’. Negotiation is the
process of bit-rate adjustment. To negotiate bit-rates up press “F2” then “3”, or
for lower bit-rates press “F2” then “9”.
The relationship between Line Quality, modem negotiation and retraining is
described in further detail in the
POTS
menu section of the full manual under
Auto Renegotiate
.
8.3.
POTS Operation Precautions
T
ieline
codecs are very reliable but a codec’s performance will only be as good as
the line that it is operating over. When using a POTS line, proper precautions
MUST be taken to ensure that only the
T
ieline
codec uses the line. Please ensure
that you remove these possible interference sources:
DSL or ADSL Modems;
Other telephone handsets;
Portable phone base stations;
Unused parallel phone sockets;
Fax machines;
Computer modems;
Burglar Alarm systems; and
Extension bells.
8.4.
Call Waiting
Call waiting tones may cause the codec to malfunction. Most phone companies
supply call waiting as a feature and you will need to turn it off. In the internal
phone book, program the number for disabling call waiting, and dial it before
calling anyone
