Is it possible to use HT813 ATA without PBX?



I don’t know a lot about IP telephony but I know a few.

I use some grandstream ip phones in my office and work great.

Now, I want to use my standard analog phone line in my home with an IP phone, without any PBX.

Can I connect my standard analog phone line to the FXO port of the HT813 and then create a SIP account to my IP phone to connect to the HT813 to make and receive calls through the FXO port?


It is not easy to do, so if you lack knowledge i suggest ask pro (well i think it is easy but was reprimanded that it is not easy).


Thank you Marcin,

I will be back for a feedback after complete the installation


Remember to set correctly PSTN (can be challenging)
In general it is not much different then Ht-503 so follow their manual:


Hi kkkk: was you able to connect sip software to HT803 and make PSNT calls witout PBX?
Can you explain how, please?





I have just installed the HT813. I received it an hour ago.

Now, I can make outgoing calls using an analog phone connected to FXS port and the PSTN line connected to FXO port.

I haven’t succeded to make outgoing calls from my IP phone.

I will try it and I wil be back for feedback.


Hi Marcin,

I set FXO Port in the same way as on HT503.

I cannot register as this SIP user on my IP phone.

Do you have anything to suggest?


You do not register, uncheck register.
It is IP-IP connection only.
In phone: add server as HT IP:port (usually port is 5062 - you can find it in FXO page) and gateway set up same as for other gateway (there is no difference here at all if end point is phone or gateway).


Sorry for asking again.

I setup FXO port of HT813 with an IP at 5062 port.

Also, I setup a SIP account on HT813, without any registration required.

Then, I setup DP720/DP750 with a new profile for the IP of the HT813.
What have to set on DP750 as SIP Account Settings to access the FXO port of the HT813?


SIp Server as HT+port
Turn off register.


These are the screens from HT813 and DP750 admin page.

Is it possible to find out the problem?


Where is port in DP ?

Also DP profile 3 is not on 5060 so you need modify server in HT for correct port (also forward).


ok. I fixed the ports.

Now, when I make a call from DP it rings the phone that is connected to FXS of HT.

Also, when I call at 8888 (the SIP of FXO) also happens the same, the phone at FXS rings.

Anything to help?

How can I access the PSTN line connected to FXO ?


Ring: wrong port. Check FXS and FXO port, they should be different. Put FXO port to DP.

Did you set forward on Basic page (HT) to DP ?
Also you can turn of this FXS ring in HT on FXO page.


It is a little bit confusing!

Anyway, the fxo socket on HT goes to PSTN. The fxs socket of HT goes to an analog phone. So, no problem from here.

I can’t find a solution right now. I will continue this task in a few hours.

Thank you very much for your support.


In addition to what Marcin indicates -

I may be a little behind as I am looking at the pix you posted, but why is the SIP server setting for the IP in the HT and the DP the same? I assume you want the HT to point to the IP of the DP and the DP to point to the HT.


Thank you Ipneblett for mentioning that.

I haven’t finished the installation, but I can make outgoing calls from any IP phone through the FXO (PSTN) of HT (in addition of making outgoing calls with any analog phone connected to FXS of HT).

I have a lot of things to check.