I don't know if Nortel made changes but I found this in Nortel Business Communications Manager 450 1.0
Configuration—System
NN40160-501 01.01 Standard
August 2008
BCM450 device type capacity
The following table provides the maximum capacities for your BCM devices.
Table 1 BCM450 device type capacity
Maximum TDM Set DNs that can exist in the system (Note: DECT and T7406e wireless handsets are part of the TDM set count). Maximum is affected by IP DN count. (Available DNs = 300 - IP DNs allocated) 300
Maximum number of IP Set DNs. Maximum is affected by TDM DN count.(Available DNs = 300 - TDM DNs allocated) 300
Maximum number of Application DNs (Call Centre Skillsets, VoiceMail) 115
Maximum number of ISDN DNs 16
Maximum number of Hunt Group DNs 30
Maximum number of Target Lines (target line numbering starts at line 361)300
Target Line Number (#) Range (pre-allocated - 1 for each possible DN - 300 in total) 361-660
Maximum number of TDM Trunks (Analog, Digital physical trunks). Maximum is affected by IP Trunk count. (Available TDM trunks = 130 - IP Trunks allocated)130
Maximum number of IP (H.323/SIP) Trunks. Maximum is affected by TDM Trunk count. (Available IP trunks = 130 - TDM Trunks allocated). 130