Audio and Connectivity
While the ST55 included a loudspeaker for calls and music, it didn't have a 3.5mm headphone jack, meaning users relied on its limited sound features. It embraced downloadable polyphonic ringtones, which was a popular trend for personalizing phone alerts. However, it lacked modern connectivity options such as Bluetooth, Wi-Fi, or USB, making file transfer and internet usage minimal, constrained to GPRS Class 10.