AEC / Telco Audio Interface | Shure Conference Phone guide

5 AEC / Telco Audio Interface

This interface provides a dedicated termination to connect the discussion system directly to most external telephone hybrids or videoconference codecs, enabling users of the system to communicate with remote parties. When used in conjunction with a telephone hybrid, the ConferenceONE™ discussion system can communicate with distant parties over standard telephone lines. When used in conjunction with a videoconference codec, the ConferenceONE™ provides the audio portion of a videoconference. To avoid returning echoes to the distant party, the device must provide effective acoustic echo control (AEC). The ConferenceONE™ discussion system does not provide this echo control function.

5.1 Interface Levels

The interface provides professional balanced line level signals; a nominal level of 0 or +4 dBu. Level Adjustment switches, set next to the terminal blocks, allow for optimum level matching to a hybrid/codec that may require higher or lower than nominal speech signal levels to properly operate. To maintain the same input and output level the switches should be set to

the same position. If the hybrid/codec provides weaker than nominal receive signal levels from the remote party (received speech in the ConferenceONE™ loudspeakers is perceived to be lower in level than the local speech), the switches can be set to the “-5 dB” positions to match the lower than nominal Receive Input signal level. This will boost the received speech heard from the loudspeakers and lower the level of transmitted speech. The opposite effect results with the switches set to the “+5 dB” positions. Note that these switches cannot be expected to compensate for poor line conditions. For reliable teleconferencing, the external telephone hybrid or videoconference codec needs to be capable of providing consistent receive signal levels to the ConferenceONE™ over a range of conditions.

5.2 Balanced / Unbalanced Connections

The 6-pin terminal block provides a balanced input and output audio connection to the system. If the hybrid/codec uses unbalanced inputs and outputs, make connections to the ConferenceONE™ “+” terminals and ground, leaving the “-” terminals open.

5.3 External Interface Device Settings

For information on the required settings of the external telephone hybrid or videoconference codec, refer to its user guide.

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