There are stacks of problems with Caller ID (CID) and VoIP.
SPA-3000 and Uniden 2355
The Uniden DECT cordless phone has a known problem where the Caller ID does not display CID on the PSTN line through a SPA-3000. The solution to this problem is to set the PSTN Ring Thru Delay: setting on the PSTN Line page to 0. If you are an Engin customer with a locked box, you can request that Engin change this setting for you. If you have an unlocked box, you can change the setting yourself.
SPA-3000 and Doro 5065R DECT
The Doro DECT cordless phone has a known problem where the Caller ID does not display CID on the PSTN line through a SPA-3000. Go to the Admin\Advanced page. Select the regional tab, and down the bottom change the ‘Caller ID’ method to ‘ETSI FSK With PR(UK)’ and set ‘Caller ID FSK Standard’ to ‘bell 202’.
This fix was posted by http://forums.whirlpool.net.au/forum-user.cfm?id=21121 on Whirlpool Forum.
Telstra Thompson Modem
There is a known problem with the Telstra supplied Thompson Speedtouch 530 modem where it will not initiate a SIP phone call. This is because port 5060 is blocked by default. The easiest way to unblock port 5060 is to do the following:
Start Telnet by selecting Start\Run\Telnet
type> o 10.0.0.138 (assuming your Ip address of the modem is the default)
type in your username and password
type> nat bindlist
You should see something like SIP 5060
type> nat unbind application=SIP port=5060
type> config save
type> system reboot
This should allow SIP traffic on port 5060.