Most ATA are used to connect analog faxes. Parameters changed here ease
fax integration.

preparing to change default values for ATA devices while leaving those of phone
devices untouched

This plugin doesn't have support for the 6757iCT and 9480iCT because
the 3.3.1 SP4 firmware is not available for these two models.

So that some fixes that have been made to the W52P plugin are also
present for other plugins.

Remove other W52P plugins.

On XiVO, when synchronizing a SCCP phone, this is actually done via
xivo-sysconfd.

Was only used by the xivo-aastra-2.6 plugin, which has been removed
earlier this year.

Remote-Party-ID causes problems with the caller id when
calling through a trunk. XiVO substitutes the number with
the SIP username, which we don't want. Deactivating
remote party id avoids this problem

DHCP integration is required for the phone model to be automatically
extracted, so if you have not / can't enable DHCP integration, your
phone will not upgrade their firmware automatically.