Avaya 3641 and 3645 (Spectralink/Polycom 8020 and 8030) wireless handsets
Handsets appear to randomly power off, even when fully charged.
Likely caused by loose or damaged connectors from the battery pack to the connectors inside the phone itself. Can be caused through general age of the handset, improper cleaning and of course, dropping the handset.
Replacing the battery would be the first port of call, but if it is the phone connectors itself that are damaged, a replacement handset would need to be sourced.
When a call comes in, or a call is made outbound on SIP and is, for example, placed on hold, the call cuts off.
From what I have seen, this is down to a codec problem in the configuration.
Connect to the system using Manager E and navigate to the following location:
Settings | Auxiliary Equipment | Announcement
Once here, you will need to check the codecs in the bottom right hand corner under:
MOH Sources | Audio Codecs
Check which codecs are configured and make sure that the top 2 are ones supported by your SIP carrier, e.g. in the UK, set the top 2 to G.729a and G.711a
As far as I know, this can only be done through Manager E and not through the Web Based Management, as this option does not seem to appear. This may change in later releases and this How To will be updated if and when it does.