We currently have a system running Ignition 8.1 vision at one of our plants. I have them setup with the voice notification module which utilizes a Grand stream Handytone (HT-813) which dials out to a phone line which works great. Unfortunately, at another location with an identical setup, the phone line keeps getting cut. Our first solution is that we used a Moxee cellular home phone base station with our AT&T sim card with the grand stream. This solution works for calls that Ignition makes outgoing, but when prompted to press any key to continue nothing works and it does not recognize the key presses. I found this same issue when we tried using this base station with a dialog elite dialer. Outgoing call would work but you could not acknowledge alarms as it seems no key presses are recognized.
My team is trying to come up with a cellular solution that we could use instead of depending on a phone line. Possibly bypassing the grand stream all together. The kicker here is that company policy states that none of our SCADA networks (HMI, PLC, Radio) can be connected to the internet. Dialers are excluded as there is no perceived threat if someone gained access to our dialers.
Has anyone run into this issue? Any solutions out there that others have used given the same limitations of not being exposed to a non-local network? I like the idea of using a cellular gateway but have to ensure there is a wall of security as the cell network is exposed.