Thinkpads Forum

I just got a new x100e and found that it has a single jack for both headphone and microphone. I already had a traditional dual plug headset and when I went to Radioshack to ask about adapter, the guy had never heard of a single jack computer before and suggested using a USB headset instead.

Anyone know:
1) If I can just use a standard 3.5m to 3.5 m Y splitter?
2) If not, are there adapters out there that will work?
3) Is the only option to buy something that IBM probably makes to fit this jack?

Thanks!
John

The same issue exists on the T400. There are couple comments in these threads that may help, though:

http://forum.lenovo.com/t5/T400-T500-an ... m-p/201262
http://forum.notebookreview.com/lenovo- ... itter.html

"the guy had never heard of a single jack computer before"
Well that makes two of us, but the key word here is "computer".

You'll find that the Palm Treo's used a single jack for a number of years now, as does the iPhone, the Androids, most of the cell phone market. These are "smart jacks" because apparently firmware is cheaper than hardware and two jacks cost more than one jack plus some tiny brains.

The "single jack" in the Treo is just one stereo 2.5mm (submini) jack, while most other phones use a simple stereo 3.5mm (mini) jack. In either case it works the same way. The phone (in your case, computer) looks at the impedance of the device that has been plugged in, and determines if it is a) one mono earpiece, b) two stereo earbuds, or c) one microphone plus one or two earbuds. A very clever idea with some exceptions. In my case, the Treo looks at only ONE stereo channel to determine whether it should sent output to the earbuds, so when I rolled up an adapter and tested just one channel at a time--only one channel would work. The "other one" needed to be connected before the brain would send any audio to either channel. Beware, your computer may have the same tiny brain.<G>

There are some 3.5mm 4-part jacks, used by Icom and others in their portable radios to carry the mic and speaker and controls all separately, but I'd expect your computer is following the cell phone standards, anticipating that you'd use the same common ear/mic adapters.


I've never seen an adapter to plug a conventional mic, plus earbuds/headset, into the unified smart socket. Given the choices in plugs and sizes, I'd think you would have to solder up your own (not hard if you know how to solder) or else just buy the earbuds/mic set that is intended for a cell phone. The computer should recognize it and sort it out all by itself.