I have been able to workaround the issue of low volume in the Polycom 320
and thought I'd share my findings.

As mentioned in a previous email, while looking through the Polycom admin
guide I found some advanced features for audio gain. The latest admin guide
can be found here:
http://www.polycom.com/support/voice/soundpoint_ip/soundpoint_ip330_320.html

There's no description of what these different settings do so I had to
figure it out on my own. Here's what I've come up with (I doubt the
technical terms are correct, but it should give you a general idea):

rx: receive gain in dB
tx: transmit gain in dB
analog: sets overall gain
digital: sets initial volume
chassis: speakerphone
handset, headset and ringer: self explanatory
sidetone: ?

Many settings allow specific values for different models. Some just have a
generic setting with no model listing. If the model of interest is listed, I
believe that is the one that should be used.

The volume that I was really interested was the speaker part (rx) of the
speakerphone (chassis). Therefore, the settings I wanted to change were
voice.gain.rx.analog.chassis.IP_330 (overall gain) and
voice.gain.rx.digital.chassis.IP_330 (initial volume). I quickly found the
following file, which appeared to have all of the settings with the defaults
set: /etc/sipxpbx/polycom/polycom_sip.cfg. The defaults for the above
settings were 0 and 5 respectively (also mentioned in the admin guide).

The next thing I needed to do was set this value in sipXecs. There is no
user interface at this time for the gain settings, so I did a bit of
research and found that best place to change this is in the
/etc/sipxpbx/polycom/mac-address.d/sip.cfg.vm file. Please see the following
page for more info:
http://sipx-wiki.calivia.com/index.php/HowTo_configure_Polycom_SoundPoint_IP
_phones_with_sipX#Changing_Polycom_Profile_Templates

I ended up adding the following between the volume and vad settings:

<gains
  voice.gain.rx.analog.chassis.IP_330="12"
  voice.gain.rx.digital.chassis.IP_330="12"
/>

After making this change I resent the profile to the phone.

After some testing, I found these are the ideal settings for us for the
speakerphone. The initial value (digital) is probably a little on the loud
side, so voice.gain.rx.digital.chassis.IP_330 may end up being lowered to
around 9 in the end.

I have noticed a number of people mention the initial volume level of the
handset is also a little low. If you'd like to change this, you would
probably need to change the voice.gain.rx.digital.handset value (there is no
model specific setting for this). The default is set to -15. Bumping this up
to around -12 may be sufficient (testing is required).

To wrap this up, I should mention that Polycom recommends not changing these
settings. If you decide to change them, I recommend changing the values in
small increments to ensure you don't cause any other issues. However, we
have made a number of test calls and have found that there is no noticeable
impact in the call quality (i.e. echo). We are very happy with the changes
so far.

HTH,
Tim


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