for MT 0.4.14
I need testers to work out the final things, at this point teleporting and 'dialing' works but no doubt there's bugs.
Works with and without Technic and Mesecons
note: without Technic, diamond blocks are used by default
By: Harrierjack based on Technic/stargate
Formspec was a copy but eventually changed completely. Some formspec textures and gate sounds are still used (at least as placeholder)
Gladly received help from:
DHD textures: DS-Minetest, Azekill_DIABLO
Formspec Icons: TBD
Stargate-like portals for Minetest.
The portal itself is a structure you have to build yourself (atm anyway), it should look like the example below and be made from carbon steel blocks when Technic and moreores mod is enabled. The block type can be changed in default_settings.txt as well as some other values but in case technic isn't available or a custom block can't be found it will always default to default:diamondblock.
Note: if you switch portal blocks mid game / in existing world all previous portals will still be registered as such, either remove 'portal_registered_portals.data' file and/or remove/replace DHD's, symbols will probably change

When you have build a portal from the correct blocks, you need to put down a DialHomeDevice (DHD) near the portal (diameter 10 or see default_settings.txt) to have it connect to that portal. The portal checks where the DHD is to see which side will be used for the teleporting 'dropzone'.
Right clicking the DHD will open the menu. The portal registrator will be the owner and can change the name or set private. At this time the only advantage of private is not showing up in the portal list.
On the left bottom you can see some information about the current portal and on the right you see public portals with their address. After entering an address press the big red button and the portal activates.

After activation the portal stays open for 8 seconds, every porting entity adds 2 more seconds to the time it stays open, and after an address is set you can also punch the portal (or use mese signal) to enable/disable the portal. Mese signal can keep the portal on (as long as there's power (or power requirement is 0 or without technic mod))
Note that the DHD needs technic HV power for the portal to function, when the power runs out the portal shuts down (keep arms and legs inside at all times :) ). The DHD and the portal work wireless (let's go with that ;) )
All public portals are connected (no discovery necessary)

As mentioned several settings can be changed in default_settings.txt. I suggest you backup the file and edit it for any personal preference, such as time portal stays open, extra time, power requirement, power type, even the shape of the ring if you like.
Requires: default game
(optional)Technic but then also include moreores for the carbon steel blocks or without moreores for diamond portals
(optional)Mesecons
License: WTFPL
Download
Github Repo
Direct Zip
Let me know what you think.
PS: the UFO in the last picture is from a seperate unrelated ufo mod and it actually works going through the portal.. if you can manage to align it correctly since it's hitbox is just a little smaller then the inside of the portal.. (anyway, I just noticed that when portal mod was almost done, when I started I never planned vehicles to be ported though it seems to work) perhaps another TODO proper item vehicle support
update: had to break vehicle support for now since it was 'grabbing' 3 other unknown entities when 1 player goes through..