Analog Coefficient Types

The device can use the following analog Coefficient types:

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FXS:

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USA line type: 600 ohm AC impedance and 40 V RMS ringing voltage for ringer equivalence number (REN) of 3

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European standard (TBR21)

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FXO:

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REN: 0.5

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USA line type: 600 ohm AC impedance

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European standard (TBR21)

The Coefficient types increase return loss and trans-hybrid loss performance for two telephony line type interfaces (US or European). The adaptation is performed by modifying the telephony interface characteristics. This means, for example, that changing impedance matching or hybrid balance doesn't require hardware modifications, so that a single device is able to meet requirements for different markets. The digital design of the filters and gain stages also ensures high reliability, no drifts (over temperature or time) and simple variations between different line types.

The FXS Coefficient types provide best termination and transmission quality adaptation for two FXS line type interfaces. The parameter affects the following AC and DC interface parameters:

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DC (battery) feed characteristics

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AC impedance matching

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Transmit gain

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Receive gain

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Hybrid balance

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Frequency response in transmit and receive direction

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Hook thresholds

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Ringing generation and detection parameters

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To select the Coefficient types:

1.

Open the Analog Settings page (Setup menu > Signaling & Media tab > Gateway folder > Analog Gateway > Analog Settings).

2.

From the 'FXS Coefficient Type' drop-down list (FXSCountryCoefficients), select the required FXS Coefficient type.

3.

From the 'FXO Coefficient Type' drop-down list (CountryCoefficients), select the required FXO Coefficient type.

4.

Click Apply, and then reset the device with a save-to-flash for your settings to take effect.