Fax and Modem Transport Modes

The device supports the following transport modes for fax per modem type (V.22/V.23/Bell/V.32/V.34):

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T.38 fax relay (see T.38 Fax Relay Mode)

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G.711 Transport: switching to G.711 when fax/modem is detected (see G.711 Fax / Modem Transport Mode)

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Fax fallback to G.711 if T.38 is not supported (see Fax Fallback)

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Fax and modem bypass: a proprietary method that uses a high bit rate coder (see Fax/Modem Bypass Mode)

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NSE Cisco’s Pass-through bypass mode for fax and modem (see Fax / Modem NSE Mode)

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Transparent with events: passing the fax / modem signal in the current voice coder with adaptations (see Fax / Modem Transparent with Events Mode)

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Transparent: passing the fax / modem signal in the current voice coder (see Fax / Modem Transparent Mode)

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RFC 2833 ANS Report upon Fax/Modem Detection (see RFC 2833 ANS Report upon Fax/Modem Detection)

‘Adaptations’ refer to automatic reconfiguration of certain DSP features for handling fax/modem streams differently than voice.