I also bought one of these units from a guy in Italy on Ebay. They are what were referred to as Endwave units a few years back. The group is here:
https://groups.yahoo.com/neo/groups/24GHzHam/info

If you look in the files section of that group there is lots of info in the units.

The units do not need any modification and work on 24 G straight off. They need a 12 Ghz LO. The Elcom Synthesisers (DFs1201) available from Art-in-Part on Ebay work well with them and again do not need any modification and can be programmed with a PIC or an Arduino over their SPI bus.

The Nortel units currently on Ebay are missing the waveguide filters which were available in the past. They need re-tuning to 24 GHz

I get about 1 W out of my units after the necessary WG switchery and they make very nice tyranverters for the band. A few of us in GM are using these units as the basis of our transverters.

73s

Brian GM8BJF
--
Dr Brian W Flynn
15 Riselaw Crescent
Edinburgh
EH10 6HN

0131 447 4043