Re: Connecting to GTOCP5 via WIFI


Hello Rick,

When I click “connect” (your step 3), I get a dialog box that says enter network security key. That’s where I get stuck.



From: <> On Behalf Of Richard
Sent: Thursday, December 10, 2020 5:38 PM
Subject: Re: [ap-gto] Connecting to GTOCP5 via WIFI


Hi David,

I’m somewhat new to this forum (a lurker) but may be able to help.  I just upgraded

the software for my GTOCP5 and checked all communication functionality (serial, ethernet, wifi)

both with the laptop (Windows 10) and through APCC-pro.  Here’s what worked for me for the wifi.

  1. Power up laptop and GTOCP5

  2. On my laptop, double click on the wireless icon.

     This brings up the available networks.  I find one network GTOCP5_NET_xx (xx is a number)

  3. I then select the GTOCP5_NET_xx  I click “connect” which connects to the GTOCP5_NET_xx network

     with the statement “No Internet, secured”

     NB:  I do not find the mount until I perform the 3rd step.

  4. I can then run the application FindMounts_VFM-01-03 (comes with the new software from the AP site).

     The application returns the above network and the IP address for GTOCP5 via wireless (note that the

     wireless IP address is different than the ethernet IP address).

  5. Run APCC-pro, type in the above wireless IP address, connect the mount and I’m off to the races.

Hope this helps,



On Dec 10, 2020, at 15:15, davidcfinch9 via <DF121819@...> wrote:


I hate to say it, but this is all "as clear as mud."

What do you mean when you say, "When you connect the GTOCP5 to a network"? Does that mean when I plug the CP5 into a power supply, with no ethernet connection? Everything works great when I am interacting with the ethernet. What factory default IP address are you referring to if I am not plugged into a network? I KNOW my GTOCP5 IP address, but when I put that in my browser, nothing works. None of the suggested URLs worked. Every one of the pings returned a "no known device" message. It is interesting that the APCC "auto-discovery" (when connected via ethernet) shows only one line that starts out with GTOCP4 (yes-four), then my known ip address and ends with GTOCP5_Net_85. When I plug that into the browser, I come up with some German text.

If there is no simple solution to all this I will just continue to use ethernet. It works great, but i was hoping to eliminate a cable connection.



-----Original Message-----
Sent: Thu, Dec 10, 2020 1:46 pm
Subject: Re: [ap-gto] Connecting to GTOCP5 via WIFI

Hi David,

When you connect the GTOCP5 to a network, your router assigns the IP address.  The factory default IP address will be active if you are not plugged into a network.  From the browser URL, just try the host name "GTOCP5_85", or "GTOCP5-85".  If that doesn't work try "
http://GTOCP5_85"  or "http://GTOCP5-85".  If that doesn't work, open a command (DOS) window and ping to it, "ping GTOCP5_85" or "ping GTOCP5-85" and see if that will locate it.  If all else fails, there are a couple utilities available at  You can use FindMounts (auto-discovery on the network), or you can run "WiFi Poll for GTOCP4 or GTOCP5 for Ethernet" to query for the IP address over serial.  If you use APCC, APCC also has auto-discovery.

Most DHCP servers in routers try to keep assigning the same IP address to the same equipment, so you should not need to discover the IP address each time.  If you still have trouble, please contact us directly, we'd be happy to help.  The advantage of putting the equipment on your network is that you don't need to give up your device/PC internet connectivity to interact with the mount.

Once you can interact with the GTOCP5 with serial, USB, or Ethernet, it will be easier to help you with the WiFi.


Mike Hanson


Dr. Richard J. Tesarek
Sr. Scientist
Particle Physics Division, Fermilab
Office:  BEG Bridge

Phone:   630.840.8609
Email:   tesarek@...


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