The MIVR engine in CCX does not support TTY/TDD devices directly. The caller would need to invoke a relay operator as they would with any other voice-only call. Once the call is transferred to an agent they could conceviably use a TTY/TDD coupler-style device to communicate with the caller. The agent cannot use a straight FXS-driven device since the ICD subsystem can perform CTI control/observation on supported Cisco IP Phones.
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