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      What is the Pin-Out for VeEX's 2.5 mm Headphone Jacks?

      Certain VeEX products offer 2.5 mm TRS audio connectors, for legacy voice features, like PDH voice channels (POTS, ISDN) and VoIP

      Signa pin-out for VeEX's 2.5 mm audio jack connectorCertain VeEX products offer a three-lead 2.5 mm TRS (Tip, Ring and Sleeve) audio connector, for legacy voice applications, like TDM/PDH-based PSTN voice frequency (VF) channels (POTS, ISDN) and VoIP (voice over IP). 

      The signal pin-out:

      Tip - Microphone
      Ring - Earphone
      Sleeve - Signal Ground

      The 2.5mm TRS audio jacks are no longer common, so in absence of the original headsets supplied by VeEX, user can source or create an adapter for the more common four-lead 3.5mm TRRS (Tip, Ring, Ring, Sleeve) stereo audio jacks made popular by smartphones. 

      2.5mm TRS to 3.5mm TRRS converter diagram

      Diagram based on standard CTIA TRRS headset wiring for PCs and phones.

      Quick Glossary

      ISDN - Integrated Services Digital Network

      PDH - Plesiochronous Digital Hierarchy

      POTS - Plain Old Telephone System

      PSTN - Public Switched Telephone Network

      TDM - Time Division Multiplexing

      TRS - Tip, Ring, Sleeve

      TRRS - Tip, Ring, Ring, Sleeve

      VF - Voice Frequency cannel or time slot

      VoIP - Voice over IP