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The DSP Audio Module A900 for M900 enables additional audio codecs for the M900 base stations.

Note: In a muti-cell set-up, each connected base needs this module to enable the additional codecs.

Part-Number: 00004445

The DSP modules adds support for the following audio codecs:

  •  VOIP codecs
    • G.729 with Annex A and optional B (NB, 8 kbit/s)
    • BroadVoice32 (BV32) (WB, 32 kbit/s) (V530B2 or later)
    • Opus (NB/WB, 10-24 kbit/s) (V500B1 or later)

  •  DECT codecs
    • BroadVoice32 (BV32) (WB, 32 kbit/s, 1 DECT slot)

OPUS codec details (requires a DSP module for M900 DECT base station)

  • Support of SILK 10 or 20 ms framing. this means that we can handle the following:
    • NB 20 ms framing – 8 calls
    • NB 10 ms framing – 6 calls
    • WB 20 ms framing – 5 calls
    • WB 10 ms framing – 3 calls

  • Supported sample rates limited to 16 kHz (SDP parameter maxplaybackrate=16000 and sprop-maxcapturerate=16000) and 12 kHz, 8 KHz.
  • No CELT. Only support for the Opus bitstream and the SILK codec. No support for CELT
  • Opus frame size of 10 or 20 ms. SDP parameter ptime=20 or ptime=10, indicates this, but this parameter just gives the RTP Packet size and as no absolute size is present in a opus package, one RTP package must contain one opus package.
  • Mono (SDP stereo=0).
  • Opus packages of type: Code 0 (One Frame in a Packet)
  • No Discontinuous Transmission (DTX) support (SDP usedtx=0), but tolerate it

This is a step-by-step installation manual.

  1. Remove the wall mount plate by sliding it upwards while the cable guide is pointing downwards.

  2. Disconnect the base station from its power source and remove the network cable. Then, unscrew the Torx screw marked in the below picture.

  3. Replace the cover plate with the A900 DSP module, which is delivered pre-mounted in its a cover plate. After inserting the A900 DSP module, tighten the Torx screw that holds the module cover in place.

  4. Reconnect the base to its power source and the network and check the Syslog in the WebUI to confirm the DSP module was detected properly.

    Syslog message: loc5 .Debug 1970-01-01T00:00:03Z 173-[ DSP module detected and initialized.]

  5. In the WebUI under the "Servers" section you can see the available codecs displayed in a list at the very bottom.

  6. Reset the codecs in the Servers section of the WebUI to confirm that the additional codecs show up in the list (press the "Reset Codecs" button).

  7. Now you can add the additional codecs.

    Note: Only the top 5 codecs in the list will be used.