External Antenna Jack
A connector that allows an external antenna to be connected for improved reception while in vehicles and/or homes. The antenna may be located outdoors for maximum signal performance.
External antenna jacks were common before smartphones, but are now extremely rare. Most modern phones do not have one.
The jack is usually hidden behind a small rubber plug on the back of the phone, or may be cleverly hidden behind a camera mirror or decorative element. Other phones hide the jack behind the battery cover, making it only semi-accessible.
Not all jack connectors are the same. Attention must be paid the type in order to ensure connector compatibility.