A Homemade Basic Key System with OBi's: Part 2 - Preparation

Post date: Jun 16, 2016 9:13:37 AM

In my previous post, I wrote about my latest batphone project: a telephone system that allows calling between a house and a garage and shares a single phone line that connects to the PSTN.

The two ATA's that this project employed were previously deployed in two different networks. The OBi100 powered my home phone, while the OBi110 powered the phones at my community workshop. Both boxes had been running for years, the workshop phone not seeing much use because people would constantly unplug it.

Both of these boxes were well outside their respective warranties, and were no longer eligible for updated firmware. To get these boxes prepared for their new life by the lake, I had to wipe their current configurations, and then manually update their firmware. In addition to the two OBi boxes I needed the following materials:

  1. A power strip because you will have little AC adapters scattered all over everywhere.
  2. A computer with an Ethernet port and a web browser. I used my tracktop (a laptop running Kali Linux) but you could use literally any computer and OS and be just fine. A laptop was most convenient for me because I could use the Ethernet port to talk to the boxes, and the WiFi to connect to the Internet to download files, Google for manuals, and read forum posts to figure out how to configure the OBi's.
  3. An Ethernet switch and 3 patch cables. This lets the computer and the two OBi's all talk to each other. Any hub or switch will do. I worked on this project in my spare time at home, at work, and at my in-law's house, so I used a tiny 5 port switch for portability. If you are using a computer with no WiFi, a fourth patch cable will connect your switch to another switch or router with Internet access.
  4. Two analog handsets with RJ11 cables. Any analog telephone would work. I started with my beige box and an old desktop speaker phone I picked up at a garage sale years ago, but the garage sale phone had numerous issues that confounded the whole project. I eventually replaced it with a very cheap Chinese-made lineman's handset.[1] Having two handsets is important so you can make sure that both lines ring on an incoming call, and that the other line stops ringing when the call is answered. You can use any analog phone for this purpose, but a speakerphone makes testing easier because you can do it hands free.
  5. Some sort of PSTN connected telephone line. I used an XLink Bluetooth adapter with my mobile, but anything that provides incoming and outgoing calls to the PSTN will do, such as another ATA (I used my home phone at one point for testing) or a cable company phone service (I used my in-law's cable phone to demonstrate the system.) My mobile phone came in handy for troubleshooting because at one point I saw the speed dial call (99#) going out via my mobile, which told me I had mis-configured something.

With the materials collected, connecting all the gear should be straight forward:

    • Plug your computer and the two OBi's into the Ethernet switch.
    • Plug the two handsets into the "Phone" ports on the OBi's.
    • The OBi110 also has a "Telco Line" port. Ignore this for now. At some point you will plug your PSTN line into this port, but for now, it's not necessary.
    • Plug in power for everything.

Now it's time to factory reset and flash stuff.

    1. On the computer, set a static IP for the Ethernet adapter to [2]
    2. Factory reset the OBi's. On both OBi's, pick up the handset and dial ***, 8, 1 and hang up. This will reset the box to the factory defaults and reboot the box. Wait a few minutes for the boxes to boot up before proceeding to step 3.
    3. Disble DHCP on the OBi's. On both OBi's, pick up the handset and dial ***, 3, dial 1, dial 0#, dial 1 to save and hang up.
    4. Set a static IP on the OBi100. Pick up the handset and dial *** 4, dial 1, enter the new IP by dialing 192*168*1*100#, dial 1 to save and hang up. This sets the static IP and reboots the box. [2]
    5. Set a static IP on the OBi110. Pick up the handset and dial *** 4, dial 1, enter the new IP by dialing 192*168*1*110#, dial 1 to save and hang up. This sets the static IP and reboots the box. [2]
    6. Open the web interfaces for the OBi's in a browser. The IP's for the 100 and the 110 should now be and respectively. The web interfaces should be and respectively. The username and password for both boxes should be 'admin'.
    7. Download the firmware for the OBi's: http://fw.obihai.com/OBi-latest.fw. Save the file somewhere that's easy to get to. You will use this file to update the firmware on both OBi's.
    8. On both web interfaces click System Management -> Device Update, click "Browse" and locate the OBi-latest.fw you downloaded in step 7. Click "Update", wait for the upload to complete. The box should reboot in a couple of minutes.

Congratulations, you have wiped your old configs, and updated the old boxes to the latest firmware, so you are all set to advance to the final round, building the homemade basic key system. You can read about that in Part 3 - Configuration Hell.

[1] The Chinese handset is not really a lineman's handset. It's not waterproof, insulated, or ruggedized in any way. Also the awesome Engrish product description called it a "butt test tester" which has been an excellent source of juvenile jokes on my part. I have offered my butt testing services to many and made several awful "tip and ring" jokes. Despite all of my butt related joking, I did not actually clip it to anyone's butt.

[2] Don't worry about the subnet mask or default gateway, these boxes won't be talking to the Internet or the rest of the LAN. Also, don't worry about the boxes not conforming to the IP address range for your LAN since these boxes will only be talking to each other and nothing else. If your LAN happens to be 192.168.1.xxx (, simply use 192.168.2.xxx in all of the steps above.