GXW4108 - how to connect AT&T SIP through gateway to analog PBX


I have an older analog PBX that I can’t replace right now. We are porting our copper POTS lines over to an AT&T SIP trunk and will be installing this gateway device do the SIP/analog translation for our PBX. I have looked and have not found how to configure my GXW4108 to make this work. I found several samples where PSTN POTS lines were being converted to SIP for use with an VOIP PBX. Does anyone know of a guide for setting this up for my situation where the SIP needs to talk analog to my PBX? Any advice is appreciated.


The 4108 is not the correct device, if I understand you correctly.

If you were to have kept the analog phone lines and replaced you existing PBX with a IP-PBX using SIP, then the 4108 would take the analog lines and convert to SIP for connection to the IP-PBX.

I think your desire is to do the opposite, which is to take a SIP trunk and then take it back to an analog set of connections for your analog PBX. In this case you need a 40XX gateway.


The diagram that you attached is exactly what I’m trying to do. I had talked with Grandstream through chat and explained the situation and they were the ones who told me I needed the GXW4108. Crumb. Looks like I need to return what I have and see if I can’t find the GXW4008. No wonder I’ve been having so much trouble getting this work. Thank you much for sharing your expertise. .


Yes you need FXS gateway, 100%.


Thanks for confirming.