If you haven’t realized it from my previous post, I am a fan of Google. So, besides syncing my iPhone contacts with Google, I also sync my Calendar.

I don’t have a Mac (YET), and I don’t have a copy of Microsoft Outlook, so I pretty much don’t have anything I can sync with on my Vista Desktop and XP netbook. Without Google, all I can do is backup my calendar to iTunes.

So, prior to OS3.0, I have setup my iPhone to do over-the-air activesync just for my calendar. It worked great and I loved it. What really surprised me that it also took care of subscribed calendars. e.g. My wife shares her Google calendar with me, and that also syncs to my phone; I also subscribe to a public holiday calendar for Singapore, and that syncs to my phone as well.

What impresses me is that once you have more than 1 calendar sync to the phone, all the items will get color coded. E.g. my calendar items will show up with a blue dot, my wife’s an orange dot, etc… On top of that I have permissions (set in Google Calendar) to add/delete/modify my wife’s calendar and I can do all those on the iPhone as well. There’s an option for me to choose which calendar an item is for when creating it.

When I was just surfing around on what’s new and what people are doing, I came across the new feature of the iPhone OS 3.0 and also supported by Google. That feature is caldav sync, as opposed to activesync. So, what’s the differences?

In short, very few differences. I’ll list the few I know

1. Activesync – just need to setup your main account, and everything that is subscribed to in the Google Calendar interface will show up automatically
2. Caldav – each calendar must be added for it to show up in iPhone, so this is more tedious.
3. The advantage here is that activesync and caldav can both be used at the same time! A lot of people will likely sync their calendar with the office calendar via activesync. By using caldav, you can then also add on your personal calendar from Google. Lot’s of feedback I read in forums is that people are really pleased to be able to have both their work and personal calendars in the iPhone AT THE SAME TIME, and still kept separate. This is one of the biggest advantage, the marriage of both protocols.
4. One thing that is important for me is reminders. In Google Calendar, you can set to receive multiple reminders for an item. E.g. for important events, I like to set pop-up reminders 10hrs, 1hr and 15mins before the event time. The activesync protocol only allows one of the reminders to go through to the phone, however caldav will sync all through. So, my phone will alert me at all the set reminders. Now, this is of a huge advantage for me.

As you probably guess, I’ve dropped activesync totally and now using caldav. Just a note though, when I started using caldav, in my appointments, I can start to specify “second alerts”, which is great! However, if you have more than 2 alerts/reminders for an item, you’ll only see the first and last one. I have items with 3 reminders, and all 3 will pop up in the phone in due time, I just can’t see the settings of the middle one in the phone. But that’s only a minor issue, as I would not change the alerts, but if I need to, just need to log on to Google Calendar to change it.

I’ll just keep things short (relatively) for this post, may post a how-to setup caldav post in the future. The guides I found only managed to get me half way. Had to figure out the rest of it myself by trial and error.