thanks for replies to all of you.
i’ve worked with elastix in the past (self-hosted) and 3cx (cloud), elastix was again on some crappy machine that also had problems. why companies always re-use old pcs for running pbx is beyond me. 3cx was okayish and worked mostly as long there was internet running, but now that i wanted to self-host 3cx, i saw their subscription cost and said no fucking way to pay that much. 2 years of 3cx covers the cost of 2 ucm machines.

someone mentioned backup to a network place - yes we’ve got them. as for firewall the ucm, i don’t need internet on it and the ISP don’t have internet on the voip port anyway. so the machine can be completely offline. not sure the lan port on the UCM can support a hybrid port (native untagged vlan and a different tagged vlan) - the UCM have 3 ports (wan, 2 x lan - but the 2nd lan must be connected to the 2nc UCM for HA). i can do nat tho. or option 2 is not to use HA, and have the 2nd UCM in spare sitting nearby unplugged and when the 1st dies to simply unplug it and plug the 2nd unit. this is a more real outcome, that way i can do automatic backups too because the NAS are not in voip vlan, but in native subnet.

freepbx is , to me, complicated. it’s not as logical as elastix was, and far far away from the 3cx logic. we also don’t need softphones as everybody that is out of office has a mobile phone with ISP VPN so we all have a short 3 digit phone number as when we’re in the offices, plus the gsm gateway plays a role to bridge the pbx to mobile phone. since the whole service is from the same ISP, we pay a fixed monthly price regardless of landline or gsm minutes, sms, internet usage. so i don’t need to think about it.

so oveall - if the UCM is not a good choice for us, but we want to stay local, what is that other choice - the machine that runs freepbx ? what is that called and is it available in europe? everything we buy must be from from inside the country but perhaps a distributor can import it from europe. i bet the price would be high for such a machine and not 300eur like the ucm costs.

we’d like to have this in-house like we had till now. cloud pbx is not an option, as we need telephone service in case of internet outage, and we have them. infrastructure here is what it is. it’s also a reason we have gsm gateway. we can’t depend on internet for telephony. (we also run our servers locally and nothing is online because of internet instability).

i don’t see the pbx system as security issue if the system is completely offline from internet. for telephony we do and always will depend on ISP to provide numbering and trunks, it’s a business agreement that we have to keep landline internet, voip and mobile phones on them to get an overall cheaper service. we’re a business client and have SLA with them too.

so nobody wants to go cloud, but i’d like something that is easy to maintain. i was considering engaging an outside company to make the move from freepbx to grandstream and afterwards i’d only be managing it from time to time, setting up holidays on the machine and changing extensions when people come and go, like i do now.
why would grandstream ucm be a bad idea? 30 ext, max 5 cc… i saw yeastar centrals for triple the price and while working on a s20 i didn’t see it’s offering anything more than a grandstream, except maybe softphones, which we don’t need.