A brief review of the Grandstream HT-502 ATA

The used HT-502 2-FXS analog telephony adapter I bought from eBay arrived earlier this week, and I hoped that by this time I could write about two functional rotary dial phones happily dialing out through this device.

No such luck, but the HT-502 is not to blame. The Northern Electric 302 seems to be mis-wired, because the ATA isn’t detecting the pulse dialing at all. I’ll have to open it up and dig in this weekend. The Automatic Electric Monophone 40, on the other hand, is wired correctly but needs some adjustment: the upper digits (7 through 0) sometimes miss a click, resulting in mis-dialing.

Image from Grandstream.comThat said, I’m already prepared to give the Grandstream HT-502 ATA very positive reviews. In fact, I might like it even better than my trusty Cisco-Linksys-Sipura SPA3102.

You can read about the device on Grandstream’s web site. Here are the unmentioned features that I really like:

  • It accepts rotary/pulse dialing, without any special configuration or modification. This was the reason I bought it, and indeed, it works. The HT-503 (1 FXS and 1 FXO port) can accept pulse dialing on its FXS port, also.
  • On an active call, it accepts rotary-dialed input and converts to SIP DTMF codes. Thus you can navigate a menu tree with your rotary phone, as long as you don’t need “*” or “#”.
  • You can configure the device with a touch-tone phone (real touch-tone; “*” required), web browser, or telnet. You can also provision the device using TFTP like the “big guys” do.
  • It has an excellent debugger. In the Advanced menu, enter the IP address of your syslog server (prerequisite: set up a syslog server), and set the verbosity to DEBUG. The floodgates will open and you will be able to see every action the device performs or receives, including dialed digits from the analog ports. This is how I was able to see where my rotary dial was sticking.
  • The device can pull its own firmware upgrades over the Internet. Nice if used carefully.
  • It’s super easy to configure. I followed documentation to factory-reset the device, hooked up a laptop to the LAN port, and reconfigured it for my own network in about 5-10 minutes. 
  • Lastly–and this is a rather obscure bonus–it uses the same power supply specifications as the Cisco-Linksys SPA devices. This hardly matters except that I have one of these–a wireless bridge for Cisco SPA devices with pass-through power. I’m planning to make the HT-502 WiFi.

The HandyTone 502 has made a good first impression and I’m looking forward to getting my rotary phones fully working on it.

5 thoughts on “A brief review of the Grandstream HT-502 ATA”

  1. Question for the author. Will the Grandstream HT-502 permit dialing a distant station by use of the distant station’s IP address?

  2. Jay. Lubricatiing your WECo 500 CV set will not result in any increase in dialing speed (PPS). Most, if not all end user products were calibrated to match the Central Office switch equipment set at 10PPS avg. 20 PPS was commonly found at legacy 701 PBX attendant positions. The 701 switch, and follow on crossbar PBX switches supported 20PPS dial. When connected to the public network switch, 20PPS dial pad would not always work, based on the end office CO switch type. Typically electronic switches were provisioned to accept only 10PPS pulse dialing. Interesting is that the older, and long ago retired #5 cross bar switch would accept a 20PPS dial string.

  3. Hi Jay, thanks for your question but you have the wrong guy. This is where I got stuck–rotary dial adjustment. I did not have any luck getting my rotary dial to return at the correct speed. Oiling the governor may speed things up but I believe there’s more of a science to it than squirting some oil in there and hoping for the best. I personally could not find a good how-to online for rotary dial adjustment. It might be possible to find an old tech manual on eBay. Good luck!

  4. I WANT TO MAKE MY 500 TYPE WESTERN ELECTRIC ROTARY PHONE TO PULSE AT 20 P.P.S. OR HIGHER! HOW CAN I DO THIS? OIL THE GOVERNOR? …

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