I'm not sure if what I've got below is still correct as it's very very old, but please let me know if it's out of date.
Meridian Norstar & BCM Version Identification Details
The Norstar system type is worked out as follows, example SP 30MEE02 DR1
The "SP" Stands for the system processor number
"30" = BNR (Bell Northern Research NA & UK Systems)&
"05" Means ENC "99" = NA.
"ME" Identifies the version type (Norstar Modular 8+24)
"E" This stands for the release number & is worked out by the letter
"A" being "0", "B"="1", "C"="2", “D”=“3”, “E”=“4”, “F”=“5”, “G”=“6”,
“H”=”7”, "I"="8" & up to "M"="12" etc. I.E. The letter "E"=Version 4.
"02" = The subversion type i.e. "02" Means release 4.02.
"DR1" Is the language standard set "GP2" = Global Product 2
"NAT" = National?.
SP 30DuF01 = 5.01
All the best
Firebird Scrambler
Meridian 1 / Succession and BCM / Norstar Programmer in the UK
If it's working, then leave it alone!.