VoIPing the iPod Touch
How makers gave you the feature that Apple held back.
By Erica Sadun
It’s a maker’s dream: turn your homebrew ideas
into a concrete reality and then ship that product.
This dream came true for iPod hackers Dr. Marián
Képesi, “Eok,” and Samuel Vinson. They designed,
built, and shipped an iPod touch microphone and
developed VoIP (voice over internet protocol) software to place phone calls using that mic.
Last November, Képesi was poking around on his
iPod Touch. A postdoc at Austria’s Graz University
of Technology, he had previously worked with third-generation iPods and was interested in the new
During his explorations, he discovered an important fact about the iPod Touch’s bottom connector
port: its line-in audio was active. Live pins meant
that the iPod Touch could connect to an external
audio source. It was compatible with recording or,
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better yet, with VoIP for talking over the internet.
VoIP compatibility was a long-standing goal of the
iPhone and iPod Touch hacker community.
Képesi modded an old iPod docking cable, connecting the line-in pins to live audio, and recorded
his first sample. The sound level was very low but
the signal was live. Although Apple had shipped
the iPod Touch as a “play only” device, Képesi had
uncovered its ability to record.
He announced his discovery on the iPod Touch
fan forums, and set to work adding an amplifier and
boosting the audio-in quality. It took some searching
but he finally found a small microphone that would
fit inside a standard iPod dock connector.
Képesi then put together his parts list and posted
the circuit details so anyone could build the open
source, dockable microphone. Together, the parts
Photograph by Marián Képesi