Connecting UCM6XXX with HT813

Updated on September 15, 2023

This document describes the basic configuration to interconnect the UCM6XXX series and HT813. This is typically applied to the scenario where users would like to add an HT813 not only as a remote extension but also as an external PSTN trunk. It could be common that we prefer to grab a PSTN line in a remote location and use the carrier service on another remote office, in this case, this guide will help you implement this configuration.

There are two ways to set up the UCM6XXX series IP PBX with the HT813.

Method 1: Register the HT813 to the UCM6XXX directly.
Method 2: Configure HT813 as a SIP peer trunk.

The following illustration shows the typical setup that will be used in this guide:

UCM6XXX series include UCM620x series, UCM630x series, UCM630xA series and UCM6510.

Warning:

When the UCM6XXX series is interconnected with other HT813, it is NOT recommended to turn on “Allow Guest Calls” under the UCM6XXX web GUI🡪PBX🡪SIP Settings🡪General. Turning on this option will allow unauthenticated calls coming through the UCM6XXX series. Please be aware of the security concerns when using this option.
When using the IVR in UCM6XXX series, please be aware that if “Dial Trunk” option is turned on in IVR settings, the callers into the IVR will be able to dial outbound call using UCM6XXX’s trunk. The IVR’s permission level will be used when making outbound calls in this case. Please select proper permission level for the IVR to control the outbound calls allowed via “Dial Trunk”.

Method 1: Register HT813 to UCM6XXX

Create Extension on UCM6XXX

On the UCM6XXX web GUI, create two extensions under Extension/Trunk🡪Extensions. These two extensions are used for HT813 FXS and FXO registration.

The password for the extension will be randomly generated if not specified.

Figure 2: Create Extension 1000 on the UCM6XXX

Figure 3: Create Extension 1001 on the UCM6XXX

Create IVR on UCM6XXX

On the UCM6XXX web GUI, create an IVR extension under Call Features🡪IVR. This is to receive the calls forwarded from HT813.

In IVR settings, if “Dial Other Extensions” is enabled, the calls forwarded to the UCM6XXX IVR will be able to reach the internal extensions registered to the UCM6XXX. Also, you can assign the “Key Pressing Event” to different destinations.

Figure 4: Create IVR 7000 on the UCM6XXX

Configure FXS Port on HT813

Connect an analog phone to the HT813 FXS port.
On the HT813 web GUI, go to FXS Port setting page, configure to register the FXS port to the UCM6XXX extension 1000. Please refer to the highlighted settings in the following figure.

In this example, the UCM6XXX IP address is 192.168.5.190.

Figure 5: Configure FXS Port on the HT813

Configure FXO Port on HT813

Connect the PSTN line to the HT813 FXO port.
On the HT813 web GUI, go to FXO Port setting page, configure to register the FXO port to the UCM6XXX extension 1001. Please refer to the highlighted settings and other necessary settings in the following figures.

In this example, the UCM6XXX IP address is 192.168.5.190.

Figure 6: Configure FXO Port on the HT813 – Registration

Since we are going to use IVR when the call is forwarded to the UCM6XXX, the UCM6XXX will need to be able to detect the DTMF digits. Configure the HT813 FXO port DTMF settings as below as an initial setup.

Figure 7: Configure FXO Port on the HT813 – DTMF Settings

There are a few necessary changes to be made in the FXO termination section and the Channel Dialing section as well.

Figure 8: Configure FXO Port on the HT813 – FXO Termination

First, we should confirm which method the PSTN line is using.

If the PSTN line is using current disconnect (typical case in North America), then we should turn on “Enable Current Disconnect” and disable “Enable PSTN Disconnect Tone Detection”.

The default “Current Disconnect Threshold” is 100ms, but if you start experiencing dropped calls then you should raise this value by 100ms intervals.

If the PSTN disconnects using the tones method, then turn on “Enable PSTN Disconnect Tone Detection” and turn off the “Enable Current Disconnect” option.

For PSTN tone detection, the tone disconnect method is widely used everywhere else in the world. The North American busy tone value is “f1=480@-32,f2=620@-32,c=500/500” but these tones vary from country to country. You may look up for the settings for your country at www.3amsystems.com or download the information from http://www.itu.int/ITU-T/inr/forms/files/tones-0203.pdf.

Set “Number of Rings” option to 1. If you happen to experience caller ID issue, you may set it to 2 or 4.
Set “PSTN Ring Thru FXS” to “No” if you prefer not to ring the FXS port on incoming PSTN calls after the Ring Thru Delay. In the sample setup, it’s set to “Yes”.
Set “PSTN Ring Thru Delay” option to 1. If you happen to experience caller ID issue, you may set it to 2.
Set the “Stage Method (1/2)” to 2 for 2-stage dialing.

Figure 9: Configure FXO Port on the HT813 – Channel Dialing

Configure Unconditional Call Forward on HT813

On the HT813 web GUI, go to the Basic setting page, configure “Unconditional Call Forward to VOIP” to the IVR extension on the UCM6XXX. In this example, the UCM6XXX IP address is 192.168.5.190.

How to Dial

Once the HT813 and the UCM6XXX are set up as above, the inbound call and the outbound call will be working as described below.

Outbound call

The extension registered to the UCM6XXX can dial HT813’s FXO extension number (1001 in this example). After you get the second dial tone, you can then dial a PSTN network number. Basically, the outbound call is done in a 2-stage manner.

Inbound call

The user from the outside network can dial into the PSTN line’s number (connected to HT813). And then he/she will reach the IVR of the UCM6XXX. The IVR on UCM6XXX would allow the user to further enter the extension number or key pressing digit to reach the desired destination.