GXP-2000-Hardware-Mods

Plugging in Headset Physically Disconnects Phone's Speaker
-Grandstream has indicated that firmware cannot route rings through the phone's speaker if you have headphones plugged into the back of the phone. This is apparently a hardware design limitation, and makes the headphone jack effectively useless for many users.
-Grandstream has indicated that new phones have revised hardware which resolves this problem!
-So, the question becomes:
Are there any brave souls with hardware know-how who can figure out a hack to work around this bug?
Perhaps we could list ideas and attempts here, or on a seperate wiki page.
    • NOTE: (Dec01/05) Upon invsitgation the hardware configuration is set so that the act of connecting the headphone physically disconnects the speaker and microphone there is NO way around this without a new hardware revision, hardware hacking, or using a third party headset( one that connects inline with the handset and has a manual button) - SoloFlyer
    • NOTE: (Dec04/05) Completely disconnect 3.5mm socket for headset from back of pcb, get a push button (of the kind click on click off) splice this into the output for the handset, and into the onhook detection for the handset, drill a hole into the casing of the grandstream your done... you then have handset, speaker, and headset functionality... its is a little more complicated than this... :-/ - SoloFlyer

(use it on your own risk and be aware you lose your warranty !
Image
From left to right I soldered on a wire to each red marked soldering point. Red, Blue, Orange White. Red/Blue are for the MIC, Orange/White are for the speaker. You could simply join red and blue, then join orange and white and it would give you a state where both speakerphone and 3.5mm headset are on at the same time. Otherwise you'll need a switch that will short red/blue and orange/white seperately when in the "on" position. i.e. a DPST sub-mini switch.

On the back of the phone there's a spot just next to the headset jack that looks like a perfect place to mount a switch. However this will be at the back which may not be suitable for many users.


Take a sub-mini switch to connect the red-marked soldering pairs to turn speaker on manually after connecting headset.
(This solution is copied from http://www.ip-phone-forum.de/showthread.php?t=94873 thanks to dfroe!)

Turning your GXP2000 into a conference phone.

I've found the speakerphone for the GXP2000 to be barely adequate for 1on1, so for a group sitting around the phone it's not good enough. I've started working on a fix using the 2.5mm headset socket.

Required:

1) 3.5mm stereo male to 2xRCA female adator
2) RCA male to 3.5mm mono female adaptor
3) 3.5mm Condensor Boundary Microphone
4) RCA male to twin RCA female adaptor ( splitting the signal )
5) 2xRCA male to 1x3.5mm stereo female adaptor
6) Pair of powered PC speakers with 3.5mm stereo male plug

Speaker:
The RED RCA from part 1 plugs into the male RCA on part 4. The female RCAs on part 4 plug into male RCAs on part 5. The 3.5mm from part 5 connects into the 3.5mm plug from part 6.

Mic:
The White RCA from part 1 plugs into RCA from Part 2. The 3.5mm from Part 2 connects to part 3.

Finish:
Plug the 3.5mm stereo from Part 1 into the headset jack of your phone. If you've connected it all correctly you should hear a tone from the speakers when you hit the "Speaker" button.

I have found the Mic pickup is very quiet and am hoping if I plug some sort of amp between the MIC and phone it will sort that problem out.



Plugging in Headset Physically Disconnects Phone's Speaker
-Grandstream has indicated that firmware cannot route rings through the phone's speaker if you have headphones plugged into the back of the phone. This is apparently a hardware design limitation, and makes the headphone jack effectively useless for many users.
-Grandstream has indicated that new phones have revised hardware which resolves this problem!
-So, the question becomes:
Are there any brave souls with hardware know-how who can figure out a hack to work around this bug?
Perhaps we could list ideas and attempts here, or on a seperate wiki page.
    • NOTE: (Dec01/05) Upon invsitgation the hardware configuration is set so that the act of connecting the headphone physically disconnects the speaker and microphone there is NO way around this without a new hardware revision, hardware hacking, or using a third party headset( one that connects inline with the handset and has a manual button) - SoloFlyer
    • NOTE: (Dec04/05) Completely disconnect 3.5mm socket for headset from back of pcb, get a push button (of the kind click on click off) splice this into the output for the handset, and into the onhook detection for the handset, drill a hole into the casing of the grandstream your done... you then have handset, speaker, and headset functionality... its is a little more complicated than this... :-/ - SoloFlyer

(use it on your own risk and be aware you lose your warranty !
Image
From left to right I soldered on a wire to each red marked soldering point. Red, Blue, Orange White. Red/Blue are for the MIC, Orange/White are for the speaker. You could simply join red and blue, then join orange and white and it would give you a state where both speakerphone and 3.5mm headset are on at the same time. Otherwise you'll need a switch that will short red/blue and orange/white seperately when in the "on" position. i.e. a DPST sub-mini switch.

On the back of the phone there's a spot just next to the headset jack that looks like a perfect place to mount a switch. However this will be at the back which may not be suitable for many users.


Take a sub-mini switch to connect the red-marked soldering pairs to turn speaker on manually after connecting headset.
(This solution is copied from http://www.ip-phone-forum.de/showthread.php?t=94873 thanks to dfroe!)

Turning your GXP2000 into a conference phone.

I've found the speakerphone for the GXP2000 to be barely adequate for 1on1, so for a group sitting around the phone it's not good enough. I've started working on a fix using the 2.5mm headset socket.

Required:

1) 3.5mm stereo male to 2xRCA female adator
2) RCA male to 3.5mm mono female adaptor
3) 3.5mm Condensor Boundary Microphone
4) RCA male to twin RCA female adaptor ( splitting the signal )
5) 2xRCA male to 1x3.5mm stereo female adaptor
6) Pair of powered PC speakers with 3.5mm stereo male plug

Speaker:
The RED RCA from part 1 plugs into the male RCA on part 4. The female RCAs on part 4 plug into male RCAs on part 5. The 3.5mm from part 5 connects into the 3.5mm plug from part 6.

Mic:
The White RCA from part 1 plugs into RCA from Part 2. The 3.5mm from Part 2 connects to part 3.

Finish:
Plug the 3.5mm stereo from Part 1 into the headset jack of your phone. If you've connected it all correctly you should hear a tone from the speakers when you hit the "Speaker" button.

I have found the Mic pickup is very quiet and am hoping if I plug some sort of amp between the MIC and phone it will sort that problem out.



Created by: username_taken, Last modification: Mon 21 of Jul, 2008 (22:58 UTC) by linker3000
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