I was never able to use my call waiting function on my unlocked GSM Treo 650. It always froze up until one of the lines disconnected. Here’s how I fixed it:
- Call AT&T (I’m a former Cingular customer) and have them deactivate and reactive your call hold and call waiting features.
- Follow this URL and try out the instructions in the “Delete other software with a hard reset and data restore” section:
- I think some of my network/carrier/preferences databases had incorrect settings and/or were corrupted. I only restored the DB’s and apps I knew I wanted/needed.
- After all of this my call waiting is working as expected and I didn’t lose any data.