Google Talk - Can hear them but they cannot hear me
OS: Linux Ubuntu Precise 12.04
Browser: Firefox 30 and Chrome 35.0.1916.153 used to test this fix
Google Talk Plugin v22.214.171.124
Google Talk Plugin Video Accelerator v0.1.44.29 (settings icon top right, drop down box, Settings - choose "Chat" tab - visible left side under Voice and Video Chat)
Sound Settings: Top right Computer icon, choose System settings, then choose Input tab, then unmute microphone, then test the mic by snapping your fingers into it and watching the input level gauge change in response to the snapping. This must be working right before proceeding. Make sure the Mute is unchecked!!
Problem: I can hear people but they cannot hear me.
I switched from the old chat version to Hangouts (In Gmail, login, Chat Icon lowest left of page, left click makes chat appear or disappear above the icon). Make chat appear above icon, choose Human icon with "X" beside it for drop down box, select "Try the new Hangouts". Page reloads, with new Hangouts Chat active. Left click the Magnifying Glass Search Icon. Window pops beside, and choose the Phone icon. Enter the phone number of free call you want to make.
If you wish to use the old chat in Gmail you can, this still works, but you have to make sure the chat notification below the Human icon does not report that you are "invisible"! If it does choose the drop down box on the "x" icon and choose "Visible". If you are invisible the app cannot find you and although you can hear everyone fine they won't be able to hear you. This is the reason that Hangouts works because you cannot use Hangouts as invisible!!!!
Simple fix, but the utter simplicity boggled me for quite a long time reading internet posts attempting to fix this problem and not once was this invisible issue ever mentioned! I like the old chat in Gmail and had never tried Hangouts until now and the fact that Hangouts does not permit "invisible" pinpointed the problem when phoning out worked fine under Hangouts but not under the old chat. The difference was the invisibility factor.