Hello,
I tried all the day yesterday to get this setup to work.
RouterBoard 750
Port 1 : Gateway (192.168.2.0/24)
Port 2 : Master Port for 3,4,5 (192.168.88.0/24)
Port 3 : Vlan 1 for IP Telephony (172.16.0.0/24)
I tried a lot of different settings however I was unable to make a computer connected to Lan 2 accessing the tagging portion of Vlan 1. I tried putting a bridge but I was unsure about how to do it.
I was sure the phone was working since when I was connecting through telnet from the Router, I was seeing the website of the ip phone). But whenever I was trying to access it from anything else, it was not working. I was thinking that it was something about tagged vs untagged trunk. I tried to add the vlan to port 3 but I didn’t know what to do to make it accessible from another ports, I tried to do a default vlan and putting the port of my computer a trunk (accessible for the two vlans) but at the end, it didn’t work.
I bricked my device multiple times and I had to start back.
Michel
I am not sure exactly what you want to happen with the phone VLAN but have a look at the VLAN section in the following link:
http://wiki.mikrotik.com/wiki/Manual:Switch_Chip_Features
If that doesn’t solve the problem then upload the output from /export compact and describe what you are trying to achieve.
I simply decided to remove the VLAN. I can do tagging with the protocol or other stuffs.
I went a bit farther for my setup but still the main issue was that I was unable to access the HTTP server of my voip phone located on one port of my RB 750. It seems that when a packet was leaving an interface that was a vlan, it was tagged. I could certified that since I was able to access it from the router itself (with system telnet)
However, when I was trying to access it from not a vlan port, I was unable to access it, I was unable to set the bridge for the vlan. I even went on Linux and did a tagged interface on it. But still unable to access the same voice vlan.
At least now it’s working, I got another IP phone, I could try with it.
Michel
I learned also how to backup and restore my config, that helped me a lot to not having to start from scratch…
I’m really impressed by the quality of your routers, I’m still newbie with it but I like him a lot 
Just having all the possibilities of this OS. I should’ve requested a gigabit router instead, but we’ll say that I really tought it was the same router everywhere except for Ram.
Michel