There are many things that can be accomplished during an ongoing phone call on the iPhone. Users with GSM models (like those on AT&T) can even send and receive cellular data while talking. One drag about iOS is the fact that performing actions such as sending an email or creating a reminder while on a call means exiting the Phone app.
Sure, the phone conversation can continue, but access to the in-call controls will be lost until the Phone app is reopened manually. Enter the jailbreak tweak CallShare. Once installed and configured in the Settings, CallShare brings multiple functions directly to the Phone app. Just tap the contact name or phone number during a phone call to start.
This brings up multiple options including Message, Mail, Note, Reminder and Event. Tapping any of these selections results in an overlay within the Phone app without interrupting the call. You guessed it, notes can be composed and saved, emails sent, and events added to the Calendar without skipping a beat. Send text messages and create new reminders all with the Phone app open behind the pop-up windows.Settings for CallShare are minimal, with an option to automatically open the keyboard immediately when displaying an overlay. Otherwise the tweak will wait for the user to tap inside a text field to display the keys.
CallShare is available from the ModMyi repo on Cydia for $1.00. Check here for instructions on how to jailbreak iOS 7.x with evasi0n 7. You can also find out how to purchase and install Cydia tweaks with this guide.