GXW-4008 not supplying 48v to FXS ports

Product Model: GXW-4008 V1.3B
Software Version: Program – Bootloader – Core – Base –
Extra – CPE –

Since phones are being not powered by the Grandstream unit, they cannot go off-hook, therefore never receive dial tone. Digital side seems to be fine, can access via web page, update configuration, etc. Update/Apply/Reboot are fine. Ports are registered just fine with the SIP server.

I have two identical units with the same problem. I suspect a hardware/software version conflict or similar. It is unlikely to have two units with the same hardware fault.

Opening a trouble ticket was unfulfilling, to say the least.

Factory reset and manually reconfiguring the ports does not seem to help.


What make and model of phone?


Any analog phone.


view so it would seem a problem HW, although with the translation I do not think I have understood much (I also use the Google translator, but I often write one thing and he translates another :-P)

a couple of questions:
1 - with the account correctly set up, lifting the handset of the phone will you hear the tone of free?
2 - with the account correctly set, if you call the extension the phone rings

not less important, have you regionalized accounts?



I have a couple of these deployed and have had no issue. You should be able to take a volt ohm meter and measure the voltage coming off of tip and ring. I agree that two in a row is odd and have not seen anyone else with the issue, but I guess it always possible.


Thanks for all of the advice.

No dial tone when the phone is picked up and no ringing when it is called. The web page will show a Hook status of “Ring”, but the phones do not ring.

Yes, I looked with a volt meter across the tip and ring and there is nothing.

lpneblett, do you have the same hardware revision (V1.3B) and software versions that I listed above? I suspect that my hardware and software versions are not compatible together.


99% failure if you are sure of what you did


Hardware failure? Two units with the identical failure? I am considering to disassemble and look inside. Maybe there is a fuse inside? Or physical evidence of failure?


In fact it seems strange to me, do this test, try to make a format factory, then record only one door on a trunk and tell me if anything changes


I think you are asking me to do “Factory Reset”. Even after doing that and nothing else, the analog ports are not responding to off hook. Normally, after a reset, you could change the IP address using the voice menus from one of the extension phones. But that’s not working, so I must move to the other ethernet port and access the web page from there.

The Factory Reset does not change the software versions, it only restores all of the optional selections back to their original settings. This is why I think my software is not compatible. Or it could be hardware failures within both units.


I can not help but give you advice, it’s difficult with the product in your hands often, figured without having it :slight_smile:


I did disassemble one unit. There is one screw visible on the bottom, but there are 3 other screws hidden under the 4 rubber feet. Pry off the rubber feet and remove the revealed screws to take the top off. Two more screws hold the circuit board to the base. I was looking for burnt or swollen components, but the board looked perfect, right out of the factory, both sides. Not all hardware failures leave visible indications, but I really think the software is not properly initializing the hardware. I took pictures of the cicuit board, but I don’t see a way to upload them here.


Searching through old release notes reveals that upgrade included boot loader My unit still has bootloader Could that be causing my “hardware” problem? Going back through firmware zip files that I could find (grandstream web site is not very helpful), most only include file gxw4008fw.bin and none of the other firmware files. But Firmware Version included gxw4008basea.bin, gxw4008base.bin, gxw4008boota.bin, gxw4008corea.bin, gxw4008core.bin, gxw4008extraa.bin and gxw4008proga.bin.

So, I put all of these files on a TFTP server and tried to upgrade by telnet, but it did not work…
UPGRADE> upgrade
You have chosen to upgrade the firmware.
Do you want to continue (y/N)? y
Upgrade process started…
gxw4008fw.bin is not valid for upgrade
gxw4008corea.bin is not valid for upgrade
gxw4008basea.bin is not valid for upgrade
gxw4008proga.bin is not valid for upgrade
gxw4008extraa.bin is not valid for upgrade

So, is there a trick to force these to be loaded (downgraded)? Then I could step my way sequentially through the updates, which was the typical method that grandstream required, even though they do nothing to help the users find all of the intermediate versions.


opening the equipment risks only to invalidate the Warranty


Open ticket to GS, then can supply firmware.


No firmware versions seem to do any good. One of my two units has a single port that provides dial tone and the IVR. Two of the other 7 ports power the phone, but have a white noise sound on them. 5 are completely dead. The other unit has no ports that work, all dead. What caused these once useful units to turn into crap? Grandstream will not provide schematics of the circuit board, so I can investigate if the hardware has failures. They also apparently offer no repair service, either. Buyer beware.