Push Alarms are one way how Pocket Informant can provide alarms for events and To Dos to your iPhone. Push Alarms can have a sound associated to them that you configure and when they arrive you can view the item the alarm is for. They are a great way to use Pocket Informant for all your calendaring and To Do reminders!
Apple calls these "Push Alarms" because they donʼt actually exist on your device but instead are pushed to your device from the Apple Push Notification network. If you enable Push Notifications for Pocket Informant (done in your Settings app, by default they are on), then as you add/edit alarms to your Events and To Dos, the alarm information is sent up to a WebIS server. At the designated time, this server then sends the notification to Apple's Push Notification server, which, in turn, delivers that notification to your device. Note that this means your device must be on a WiFi network (or your phone company's cellular network for iPhone users) to receive this notification. This typically isn't a problem for iPhone users unless you are in Airplane Mode or are completely out of range of your cellular service.
Pocket Informant uses Push Alarms because the iPhone OS currently does not allow third party developers to access the built-in calendar & alarm system. Currently, Push Alarms are the method that Apple is encouraging developers to use to provide alerts to the iPhone & iPod Touch.
Limitations
Push Alarms are a great new feature but have a small number of limitations due to the architecture.
- You have to be connected to a network. Push alarms work best with 3G service. iPod Touches which are not connected via WiFi may experience delays of up to 30 minutes.
- Outgoing port 5223 needs to be open on any and all firewalls
- If the screen is not on, or the device is not tethered, it will go into a "poll" mode, where it wakes up every 30min or so and checks the server for notifications
- Apple has told us that in some cases some ISPs do not properly resolve the "push.apple.com" IP and this may be a cause of Push not working.
- if you do a ping to "push.apple.com" it should resolve to 17.149.36.71
- This is not an issue WebIS can resolve - its Apple's Push architecture and unavailability of local alarms
- You must run Pocket Informant at least
once a week for the Push Alarms to be generated for the upcoming two
week period so that you donʼt miss any alarms.
- Push Alarms are
static on the server so in some rare cases its possible for a deletion
of an alarm or event not to be reflected quickly enough on the server
leading to you receiving an alarm that youʼve already deleted. Weʼve
built an extremely efficient and robust architecture so this should be
rare.
- Apple does not promise any service-level reliability for
push notifications. In our tests Push Notifications typically arrive
within 5 seconds to a minute of the alarm time. However because
notifications are network based if there is any network congestions,
slowness or other network related issues you may experience some push
alarms being late. We have not seen this during testing, but it is
possible.
- Push Alarms may not work on a Jailbroken phone due to limitations on Appleʼs end.
