For anyone else struggling with this for Odoo 9, Andreas's answer works but you need to replace references to 'email.template' with 'mail.template' in the python code. 

You may configure any sort of alarms (emails and notifications) for any Odoo objects. Have a look at the section "Special Feature" at this page: https://apps.odoo.com/apps/modules/9.0/joint_calendar/

I have made module  reminder_phonecall 

It adds Reminders field to phonecall form, which works the same as in Calendar/Events. You can select "15 min notif", "1 day notif", "1 hour mail" etc. So, you can easily get instant or mail reminder (or both).

Also, it creates Calendar Event. So, you can use Calendar as a agenda.

The module is based on reminder_base, which can be applied to any model with Date field. E.g for Next Action in opportunity: reminder_crm_next_action

hello,

I've tried these steps but I didn't receive the reminder

Why can be?

Regards

I solved this problem in slightly different way.

there is a button Schedule a Meeting

Just replaced a Schedule Other Call with a Button (Schedule a meeting renamed to Schedule a call) which allow you create an event so once you set a new event you will get a notification on the screen and by email :)

:)

Is not perfect but ... ;)

I saw thath the system time in openerp are more or less acoording your GTM, so the email works only if you do not set trigger date, but that isn't very usefull, look the postgres BD in the crm_phonecall table and you can see the date stored in the phonecall.