Is it possible to configure two different VLANs for VoIP, on an MS350 switch, for two different model IP phones on the same port? We’ve got different headers on the DHCP scopes, but I can’t see an easy way to add more than one VLAN ID on the config screen!
Short answer: You probably can't. Unless you manually configure the phones to tag their traffic with a specific VLAN and then use a trunk port as suggested by @Uberseehandel.
This is a very static configuration though and it's also not very secure. If you have the option to use a RADIUS server you could assign a different VLAN for different sing-in credentials / phones. The phone logs in and RADIUS assigns a VLAN based on some criteria of the phone's credentials or properties (like group membership for example). This way you can plug in your phone where ever you want (=move it if need be) and be sure it always gets the correct VLAN. Basically RADIUS is telling the switch which VLAN to use for this port after the device authenticates regardless of what is configured on that port.
Perhaps I should have written „potentially less secure“ since (again: correct me if I‘m wrong) you can‘t do authentication on a trunk port. „not very secure“ was bad phrasing, thanks for pointing that out.