Even though the 5510 was revolutionary, it technically wasn't the first phone with an MP3 player. The Siemens SL45 introduced this feature almost 4 months before, in August 2001! : r/vintagemobilephones
Timeline: 2001 : A Call from the Past - 10 Years of Mobile Phone Development - HardwareZone.com.sg
Mp3 Player; Play - Siemens SL45 User Manual [Page 27] | ManualsLib
Siemens SL45i - User opinions and reviews
Siemens SL45 GSM mobile
Siemens SL45 was the first mobile phone with memory expansion and an MP3 player, which debuted in 2001. I have one with 32… | Classic phones, Phone, Old cell phones
Siemens SL45i Specs - Technopat Database
Podróż w czasie: Siemens SL45, czyli pierwsza komórka z MP3
Siemens SL45 - Full specification - Where to buy?
Siemens sl45 piękny adapter mp3 cały komplet | Warszawa | Kup teraz na Allegro Lokalnie
SIEMENS ADAPTER MP3 + KARTA 32MB DLA SL45 SL45i - 9024909197 - oficjalne archiwum Allegro
Buy Siemens SL45 Mobile Phone with MP3 Player
Siemens SL45. Телефон с mp3: 680 грн. - Мобильные телефоны / смартфоны Каменское на Olx