Lessons in Hanafi Fiqh: The calls for prayer

The call for prayer ('athaan)

The call for prayer is a ascertained merit (sunnah) for the five obligatory prayers and the Friday Prayer only.
In the call for the Fajr Prayer the words "assalaatu-khayrum-min-annaum" are added twice.
The call for prayer is not made before the time of the prayer has entered, because its purpose is to make the entry of the prayer time known.
Abu Yusuf and al-Shafi3y said that it's allowed to call for prayer in the second half of the night before the Fajr Prayer.

The call to stand up to pray is like the call for prayer, but its performed to announce for people to get ready to pray and stand in rows.
Unlike the call for prayer it is done quickly. The words "qad-qaamat-issalaah, qad-qaamat-issalaah" are added also.

This preferred for the caller for prayer to be a good, knowledgeable Muslim.
In both of the above calls, the caller should face in the same direction as one does in prayer. It's disliked not to do that.
One does not whisper the two professions of Islam before they are said loudly in the call for prayer.
When one says "hayya-3ala-ssalaah" one should turn towards the right without moving one's feet. When one says "hayya-3ala-lfalaah" one should turn towards the left without moving one's feet.
It is good for the one who is performing the call for prayer to put his right index finger in the right ear, and likewise on the left side.
It is a merit to have ablution when calling for prayer.
It is disliked to make the call to stand up to pray without ablution.
If the call to stand up to pray is made by someone in greater ritual impurity (in need of ghusl), then it needs to be repeated. However, if it is not repeated the prayer is still valid.

If someone wants to pray obligatory prayers that he has missed, then he should make the call for prayer and the call to stand up to pray, even if he is alone.
If he wants to pray several missed prayers then one call for prayer is enough, but he should make the call to stand up to pray for each one.
The traveler calls for prayer and makes the call to stand up to pray when he wants to pray. It is disliked to not make any call, but enough if he just makes the call to stand to pray.