TrueSpeech® Co-Processor
PRELIMINARY/CONFIDENTIAL
Version: 1.18
9.23
Test Modes
The CT8022 includes test modes that are useful in verifying device and system operation.
9.23.1
Test Mode 1: Count Mode
Command: 511FH
Status:
511FH
In this test mode, data received from the external CODEC by the record channel is discarded and replaced by an 8-
bit incrementing count. This is intended for use in a-law/µ-law speech mode, where the 8-bit CODEC receive data is
passed directly to the Host.
9.23.2
Test Mode 2: Digital Milliwatt
Command: 511DH
Status:
511DH
In this test mode, data received from the external µ-law CODEC by the record channel is discarded and replaced by
the CCITT G.711 a-law/µ-law digital milliwatt (0 dBm0) code sequence. This is a sequence of eight repeating bytes
(a-law/µ-law samples) representing a 1 KHz sinewave at 0 dBm0.
9.23.3
Test Mode 3: Loopback
Command: 511CH
Status:
511CH
In this test mode, data received from the external CODEC by the record channel is discarded and replaced by the
CODEC output data from the transmit (playback) channel. The playback channel is not affected by this mode of
operation. The playback speech data is also transmitted to the output CODEC.
Note: Receive CODEC to transmit CODEC loopback can be performed by the Host with the CT8022
operating in normal mode. To do this, the Host simply copies µ-law frames from the record (receive)
channel back to the playback (transmit) channel.
Use this command to support tone generation to the compressed speech direction (e.g. for generating far-end
ringback tone).
9.23.4
Exit Test Mode
Command: 511EH
Status:
511EH
This command is used to exit test mode and return the record and playback channels to their normal operating mode.
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DSP GROUP, INC., 3120 SCOTT BOULEVARD CT8022A11AQC FW Revision 0118
SANTA CLARA, CA 95054 PH: 408 986 – 4300 FAX: 408 986 – 4490
All specifications are subject to change without prior notice.
ETC [ ETC ]
