You should consider setting up a basic Asterisk SIP server for testing. Something like FreePBX. I imagine there being a number of non-standard behavior with something like Vonage.
I really like the design of this intercom. The thin profile and simplicity of it. I think the USB module design makes a lot of sense as well. I could live with the lack of an "app" with good SIP support, although offering some form of an app or purpose built SIP based app (with door release button) would be smart for them considering the segment the device falls in
The real issue though is the price is just way to high for the majority of customers. At those prices you are probably looking at more advanced systems.
One note, in your comparison video you mention "mounting options" and state that they all have flush mounting. But the Axis A8207-VE doesn't have a flush mount option to my knowledge (and is considerably deeper).
In therms of price: Commend is one of the global leaders in the segment of professional intercom with a company history of 50 years now and a enterprise only solution. The power and advanced features comes with the server where you can connect thousand of stations and connect multiple site globally with each other. This may explain it.
I think, some of the weaknesses, are coming from the fact that Commend is focusing on the Enterprise segment, and however I/O is a relevant question, they are aiming to do many things through that USB and/or other peripherals.
Up to my knowledge, as I'm working with them, not so closely yet, their intercom modules, can be put in the real context only with their SW and integration solution background. Commend Studio have some really cool features, and ID5 is just a doorphone without the background.
you described this pretty good. Commend is an Enterprise solution with highest security standard in the industry and therefore I/Os at the door are a critical point. As you mentioned we have special I/O modules and also an advnaced Secure Connector for outdoor appliacation with I/Os which is paired to the station and physically disconnects everything when someone tries to hack or manipulate any part of the exposed system.
Your also correct that the Server or our Cloud Service plays a crucial role when it comes to features. Basic SIP as you mentioned is like a doorphone but professional Intercom goes way beyond telephony with complex control room audio solution and multi site connection.
Totally agree the software needs to be fixed. Sip is a non starter un residential. That said, the demand for a bi directional video screen is in demand, and there is no one satisfying that need. Wether Seidel, door king, holovision, door bird, n2, there is nothing that is doing what the ID5 is doing. Additionally with the exception of N2 the residential systems are still a pain in the ass (hello iDor).
Nearly all intercoms can be removed with, at most, a security bit on a screwdriver. This is, importantly, from the unsecured side of an entry. The relays that some integrators use that are on the backs of intercoms are typically tied into either the rex or another input of the ACS programmed to be a valid pulse of the door.
If you don't see the issue here, then get out of the security business.
A simple twist these 2 wires together and gain, as all installed systems believe, approved access should only be a thing in the movies. While I agress there are uses for I/O on the intercoms, door release is not one of them. To compare pricing and features of a properly designed and secured entry, include all additional devices required by the manufacturer to place the relays for the door release in the same secured area as the ACS module for the door. Even POE enabled ACS devices are at least on the secured side.
With all of the interest in reader formats and how secure they are, there should be equal interest in the other devices connected to the ACS.
it all depends on the degree of security but as Commend is a enterprise solution you are correct. We therefore use a Secure Connecter with I/Os which is technically paired to the station and placed inside the building. When someone tries to manipulate the station or any part of the exposed station - our secure Connector physically cuts the electric and physical connection.