I can´t call from FXS por t to PSTN and call from PSTN to line connected to FXO port in HT813



Excuse me but i bought an HT813 the trunk FXO and FXS port are registered, th versión of Gateway is the last, but isn´t posible call from FXS port to PSTN and from PSTN to line conected to FXO port

I appreciate your help




The 813 is a two port device one of which is is FXO, the other FXS. The physical RJ line ports are meant to be used with an analog device (phone) on the FXS whereas the FXO RJ port is meant to accommodate a PSTN (POTS) line.

Depending on your use case and how set-up, yes, it is possible to use the FXS to make and tale calls using the FXO port. It is also possible to use the FXO to receive calls from the PSTN which can be taken at the FXS or to the device (IP-PBX or other IP device) to which the FXO port is registered.

It is all about how you have it is configured and what it is connected to.

Will need more detail, if the above did not answer your question.


Hi ipnebltett

The FXO where we connected the line pone is regsitered, we have the HT813 connected to Freepbx, we have an auxiliar offfce In Bogota , then we need to connected the HT813 to Freepbx to have and extensión in Bogota and the line in Bogotá connected to PSTN Bogotá, now if we call from Bucaramanga to Bogotá extensión that´s ok, but if we want to call number of PSTN from external line don´t function and if we can call from office line to another line in Bogotá don´t function, because when i dailing the call is stablish only one second ring only one time and down, we tried to do the same configuration HT503 with HT502 suggest by grandstream but don´t fuction

We appreciate your help


Carlos Moreno


SO, I think you are indicatng that FPBX is located in Buca and that that the HT is in Bogata… The FXO rj port is connected to a PSTN line in Bogata and the FXO registration is occurring back in Buca, is this correct?

It is not clear to me what extension is in Bogata as you did not state anything about it other than you can call it. Is this an analog phone that is connected to the FXS port, but also registered back to FPBX in Buca?