Texas Instruments 4000M - Manual (Page 80)

Microphone and Headphone
The TravelMate 4000M comes with a microphone and headphone kit (TI Part
No. 9793399-0001).
Microphone and Headphone kit
This kit also supplies software that configures your notebook for the
microphone and headphone. To plug in your microphone, insert the plug into
the Mic connector on the front of the Portable CD-ROM Docking System. The
headphones may be plugged in either at the CD-ROM player (pre-amp) or at
the Portable CD-ROM Docking System.
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