https://en.wikipedia.org/wiki/Phone_connector_(audio)
Mobile phones[edit]
The
iPhone uses a 4-conductor (TRRS) phone connector (center) for its headset (microphone and control button right).
Three- or four-conductor (TRS or TRRS) 2.5 mm and 3.5 mm sockets are common on
cell phones, providing mono (three conductor) or stereo (four conductor) sound and a microphone input, together with signaling (e.g., push a button to answer a call). Three-conductor 2.5 mm connectors are particularly common on older phones, while four-conductor 3.5 mm connectors are more common on newer smartphones. These are used both for
handsfree headsets (esp. mono audio plus mic, also stereo audio plus mic, plus signaling for call handling) and for (stereo) headphones (stereo audio, no mic). Wireless (connectorless) headsets or headphones usually use the
Bluetooth protocol.
There is no recognised standard for TRRS connectors or compatibility with three conductor TRS. The four conductors of a TRRS connector are assigned to different purposes by different manufacturers. Any 3.5 mm plug can be plugged mechanically into any socket, but many combinations are electrically incompatible. For example, plugging TRRS headphones into a TRS headset socket (or the reverse), plugging TRS headphones or headsets into a TRRS socket, or plugging TRRS headphones or headsets from one manufacturer into a TRRS socket from another may not function correctly, or at all. Mono audio will usually work, but stereo audio or microphone may not work, depending on wiring. Signaling compatibility depends both on wiring compatibility and the signals sent by the hands-free/headphones controller being correctly interpreted by the phone.[
original research?]Adapters that are wired for headsets will not work for stereo headphones and conversely. Further, as TTY/
TDDs are wired as headsets, TTY adapters can also be used to connect a 2.5 mm headset to a phone.
3.5 mm TRRS (stereo-plus-mic) sockets became particularly common on
smartphones, and have been used e.g. by Nokia since 2006; they are often compatible with standard 3.5 mm stereo headphones. Two different forms are frequently found, both of which place left audio on the tip and right audio on the first ring (mirroring the configuration found on stereo connectors). Where they differ is in the placement of the microphone and return contacts. The first, which places the ground return on the second ring and the microphone on the sleeve, is used by
Apple's
iPhone line,
HTC devices, latest
Samsung,
Nokia and
Sonyphones, among others. The second, which reverses these contacts, is used by older Nokia mobiles, older
Samsung smartphones and some
Sony Ericsson phones.
[14] There are adapters that swap the poles over to allow a device made to one standard to be used with a headset made to the other.
[15]
Some computers now include a TRRS headset socket, compatible with headsets intended for smartphones. One such pin assignment, with ground on the sleeve, is standardized in
OMTP[16] and has been accepted as a national Chinese standard YDT 1885-2009.
maybe thats the problem?
