Nortel Networks BCM200/400 - Manual (Page 112)

112 Chapter 8 Installing a media bay module (MBM)
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Figure 65 DS30 model
DS30 numbers are set using the number 4, 5, and 6 DIP switches on the back or underside of the
MBMs. The exception is the FEM MBM. The FEM DIP switches turn on ports, each of which
consumes one bus.
Setting offsets
Each offset represents one-quarter of a DS30 bus. Each bus supports 16 lines (32 time slots) for
most MBMs.
Exceptions:
• DTM MBMs, which support 23 to 30 lines per bus
• FEM MBMs, where each bus supports one Norstar fiber module connection.
Offsets are numbered 0, 1, 2, and 3. MBMs that require less than a full bus can be assigned a DS30
number and an offset number. This allows more than one MBM to be assigned the same DS30
number, but with a different offset number.
MBMs that can have offsets assigned include CTM4, CTM8, BRIM S/T, ASM8+, and GASM8.
For example, two CTM8s can be assigned to the same DS30 number, with different offset
numbers. However, you cannot assign a CTM8 and a BRIM to the same DS30.
Note: Double Density
The 32 time slots are important when you are working with station MBMs. The DSM16+,
DSM32+, ASM8+, and GASM8 can be configured, using the offset DIP switches, to use
each of these time slots as separate telephone lines. This, essentially, doubles your system
telephone capacity.
DS256
on MSC
DS30 bus #2
DS30 bus #3
DS30 bus #4
DS30 bus #5
DS30 bus #6
DS30 bus #7
DS30 buses
available to modules
in a 2/6 split
Four offsets per bus
DS30 buses
available to modules
in a 3/5 split