I can't speak for what you need on the Cisco side but I just went thru this exersize with a 2K and Cisco.
A good starting point is this DOC.
The Mitel instructions in the above doc are just screenshots (not complete) but it is enough for an experienced tech to muddle thru.
The instructions are for an embedded T1 module so some interpretation is required if you have an NSU and use IMAT programming. (not too difficult)
What you need:
-I might be wrong but I don't think the Embedded E1 is allowed on the 3340
- You shouldn't(can't??) mix protocols on either NSU's or Embedded so you need a dedicated NSU / Embedded E1
- Fim Module port for NSU (assuming embedded not avail)
- 1 Digital Link licence for each E1(30) channels of voice required.
- DSP module, dual or quad depending on traffic
I don't think I've missed anything but you never know.
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Occam's Razor - All things being equal, the simplest solution is the right one.