Today we are going to focus on how to set up the Grandstream HT-503. There are multiple guides but I find that many were lacking in multiple areas in order to have a fully functioning unit without deficiencies. As I had 2 HT-503 units, each one required an RJ11 for our two PSTN lines. Our cable company had the lines set up so that the primary would roll over to the secondary if busy. To separate the telephone line into two jacks, I purchased a line splitter.

In order to set up your HT-503, it must be connected directly to the computer via the LAN port. Instructions can be found in the User Manual and I would advise to update the Firmware. Type 192.168.2.1 into your browser and under Basic Settings, switch Device Mode to Bridge and enable WAN Side HTTP Access and apply. Now you can connect to your Router via the WAN Port. Determine the IP address of the HT-503 and continue with the following changes:

Basic Settings:

PSTN Access Code – changed to 0 so that that receptionist can access a dial tone if there are technical issues.

Unconditional Call Forward to VOIP – use the IP Address of the Raspberry PI and set the SIP Destination Port to 5062. The Inbound Route on the FreePBX with be discussed in Part 3 which will determine what happens after a caller dials your business number.

FXS Port:

Primary SIP Server – use the IP Address of the Raspberry PI.

SIP User/Authenticate ID – this will be the ID of the phone that reception uses. I suggest a simple three digit number, ie. 444 or 777 with a corresponding password that will be used with the Raspberry Pi. You can have two outgoing phone lines as each HT-503 has 1 FXS port. We have a 2-line phone in our office so we set up each HT-503 connect to Line 1 and 2 on the main phone. This allows the included cordless phone to be used on the other line if reception is busy with a patient with the main phone.

FXO Port:

Primary SIP Server – use the IP Address of the Raspberry PI

SIP User/Authenticate ID – this will be the ID of the trunk that connects the Raspberry Pi to the HT-503 to allow outgoing calls. I suggest using the telephone number that each HT-503 is associated with a corresponding password that will be used with the Raspberry Pi.

SIP Registration – Off. The device does not need to register in order to work. On the status page, only the FXS Port should be registered once set up with the Raspberry Pi.

Dial Plan – replace with {xxxxxxxxxx | xxxxxxxxxxx} to allow for 10 and 11 digit numbers to be dialed out via the PSTN line.

Number of Rings – 2 allows for the caller ID information to be available to be passed on to the Raspberry Pi.

PSTN Ring Thru FXS – Off. The phones should be going to the Raspberry Pi with every caller.

DTMF Digit Length/Pause – 50 ms to help decrease delay from dialing to ringing.

Stage Method – 1 is to be set as you want the HT-503 to dial the number received from the Raspberry Pi.

Min Delay Before Dial PSTN Number – 100 ms to help decrease delay from dialing to ringing.

On to Part 3…