Well, after spending... yes, you guessed it- over an hour on the phone with tech support, I was told that there was no 203NA beta.
The good news is that the issue is resolved in the beta firmware here so you get to keep your hour:
ftp://ftp.dlink.com/Gateway/dir825_revB/Beta/Firmware/dir825_revB_fw_202b01NA_beta02.zip
I had downloaded this file and looked at the release notes prior to calling for support a second time but there is no mention of this beta release resolving the SIP ALG issues that everyone is experiencing. I can tell you that it does solve the problem. I was able to place the SIP phone in the DMZ or behind the firewall and get full functionality, voice and clarity both directions after applying this update.
I did not create any port mappings, virtual server settings or other VOIP/SIP related configuration. The only thing you need to do is be sure that SIP is checked (which they all are by default) in the Application Layer Gateway area (Advanced > Firewall Settings (bottom of the page))
Some notes:
- If you are using Tools > Admin > Administration settings, i.e. WAN-side remote administration, these settings will be defaulted off. You need to re-enable them after the update, including the graphical CAPTCHA login..
- Your wireless settings will be defaulted, too. You will need to re-configure both the 2.4GHz and 5.0GHz wireless radios. Be sure you know these settings before applying the update so you can re-create the configuration
- After the update, you will still see 2.02NA in the upper, right hand corner of the screen. Click on status at the top and verify that the build date is changed to 2.02NA , Wed, 7, Oct, 2009. This is your indication that the beta installation succeeded
You should have full VOIP access after this update. Please post any issues you encounter.