Mitel SX-200 Documentation page 466

7.20 The extension capabilities may be made less restrictive by de-
leting some of the foregoing options or adding other options,
and may be made even more restrictive by including; for example,
Option 44 (Originate Only) or Option 45 (Receive Only).
D. Numbering Plan
The PBX allows a completely flexible, user-defined numbering
7.21
plan. Extension numbers can be up to four digits in length and
all combinations are acceptable provided that they do not conflict with
each other or with feature access codes (e.g., if one number is 2000,
neither 200 nor 20 can be used).
7.22 Since they are programmable, extension numbers need not be
considered when the cabling and installation are performed.
Instead, each equipment port is assigned the requested access number
from any console that has been placed in programming mode. Simi-
larly, an extension number can be changed at a later date by a simple
keying sequence from the console.
8. TECHNICAL DESCRIPTION
A. General
The SX-lOO/SX-200 system is a microprocessor-controlled
8.01
PBX
switching. The main processor which has overall control of the system
is an MC6809. It is supported by 48 kbytes of Random Access Memory
(volatile) used as a scratch pad for current activity (such as which
extensions are off-hook), and installation-dependent information (such
as access codes and extension numbers). The system also provides up
to 168 kbytes of Programmable Read Only Memory (PROM) containing
the firmware which is programmed into it at the factory.
8.02 The console contains an MC6802 microprocessor with four
kbytes of EPROM which controls the displays, and monitors
such things as keystrokes. On each trunk circuit card is an MC6802
processor with up to 4 k of PROM that controls functions such as
seizing and releasing trunks.
8.03 The PBX uses a specially developed large scale integrated (LSI)
circuit to implement a space-division switching matrix. The
basis of this space division is a 4-by-8 bit analog crosspoint switch
(MITEL MT8804) which is used throughout the system to connect any
one of 31 speech paths to any one (or more) extension, trunk, console,
receiver or tone generator circuit(s). Such connections are controlled
by the microprocessor via its data and address lines. These, together
with the card select, interrupt power and other lines, run the length of
the equipment shelf backplane and are available as required to each
circuit card. See Table 8-1 and Figure 8-2 for a description of the
backplane signals.
which uses distributed
SECTION 9105/9110-096-l 80-NA
processing and space-division
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