Nextel i58sr pinouts
The connector/pinout information may be applied to the Nextel model i58sr

 Universal Cell Phone 3-pole (mono) headset connector pinout cordless/cell phones headset/handsfree cable connector
Universal Cell Phone 3-pole (mono) headset connector pinout cordless/cell phones headset/handsfree cable connector MRLG 4-pole 2.5mm headset connector pinout MRLG pinout
MRLG 4-pole 2.5mm headset connector pinout MRLG pinout