Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
Qurʾān Bukhārī Muslim Nasāʾī Abū Dāwūd Tirmidhī Ibn Mājah Mālik Aḥmad Dārimī Ḥākim Ibn Ḥibbān Ṭabarānī Nasāʾī's Kubrá Bayhaqī al-Luʾluʾ wa-al-Marjān Ibn Rajab's Fifty Riyāḍ al-Ṣāliḥīn Aḥmad's Zuhd Suyūṭī
bukhari:605 – Sulaymān b. Ḥarb > Ḥammād b. Zayd > Simāk b. ʿAṭiyyah > Ayyūb > Abū Qilābah > Anas > Umir Bilāl > Yashfaʿ al-Adhān

Bilal was ordered to repeat the wording of the Adhan for prayers twice, and to pronounce the wording of the Iqama once except "Qad-qamat-is-salat".  

البخاري:٦٠٥ – حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ قَالَ حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ عَنْ سِمَاكِ بْنِ عَطِيَّةَ عَنْ أَيُّوبَ عَنْ أَبِي قِلاَبَةَ عَنْ أَنَسٍ قَالَ أُمِرَ بِلاَلٌ أَنْ يَشْفَعَ الأَذَانَ

وَأَنْ يُوتِرَ الإِقَامَةَ إِلاَّ الإِقَامَةَ  

See similar narrations below:

Collected by Dārimī, Suyūṭī
darimi:1231 – Sulaymān b. Ḥarb > Ḥammād b. Zayd > Simāk b. ʿAṭiyyah > Ayyūb > Abū Qilābah > Anas > Umir Bilāl

Anas reported; Bilal was commanded to pronounce Adhan in double pairs and IQAMAH in single pairs. Hammam added in his version; “except IQAMAH”. (Using translation from Abū Dāʾūd 508)   

الدارمي:١٢٣١ – حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ عَنْ سِمَاكِ بْنِ عَطِيَّةَ عَنْ أَيُّوبَ عَنْ أَبِي قِلَابَةَ عَنْ أَنَسٍ قَالَ

«أُمِرَ بِلَالٌ أَنْ يَشْفَعَ الْأَذَانَ وَيُوتِرَ الْإِقَامَةَ إِلَّا الْإِقَامَةَ»