The Coeff.dat Configuration File - 3Com V7111 - VCX 4 Channels Analog FXO Media Gateway User Manual

Set the Boot file name in the BootP server: mp108.ini.
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10 Activate the BootP and TFTP servers and reset the VCX V7111 Gateway (See
"Provisioning for SIP

The coeff.dat Configuration File

The purpose of the coeff.dat configuration file is to provide best feed and transmission quality
adaptation for different phone line types. Two different coeff.dat files are needed for VCX
V7111 FXS and FXO Gateways. The file consists of a set of parameters for the signal
processor of the loop interface devices. This parameter set provides control of the following
AC and DC interface parameters:
DC (battery) feed characteristics
AC impedance matching
Transmit gain
Receive gain
Hybrid balance
Frequency response in transmit and receive direction
Hook thresholds
Ringing generation and detection parameters
This means, for example, that changing impedance matching or hybrid balance requires no
hardware modifications, so that a single device is able to meet requirements for different
markets. The digital nature of the filters and gain stages also ensures high reliability, no drifts
(over temperature or time) and simple variations between different line types.
The coeff.dat configuration file is produced by 3Com for each market after comprehensive
performance analysis and testing, and can be modified on request. The current file supports
US line type of 600 ohm AC impedance and 40 V RMS ringing voltage for REN = 2.
In future software releases, it will be expanded to consist of different sets of line parameters,
which can be selected in the INI file, for each port.
To support different types of countries and markets, it is necessary to support loading of a
new Coefficients.ini file. This file consist of AC and DC line parameters for the peripheral
devices. This file is loaded into the VCX V7111 using the TFTP, in the same way as for the
tones.dat file.
3Com VCX V7111 VoIP SIP Gateways User Manual
Operation" on page 67, describing VCX V7111 provisioning).
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