Specifications

Page 8–2
FOCUS System Manual
ceiver provides communications along a E1 line to
the network.
All data and control information is communicated
by 2.048 Mbps serial streams conforming to
Mitel’s ST-BUS format.
The ST-BUS is a time division multiplexing
(TDM) serial bus. The serial streams are divided
into 125 µs frames of 32 8-bit channels.
The Framer Module’s technical specifications for
E1 are shown in Table 8-2.
8.2 Application
8.2.1 Framers Used in T1 Systems
(T1, TE1)
The Framer Module is an essential component in
a FOCUS chassis. It forms the vital link in the
network by providing the T1 multiplexer, which is
the standard communication protocol for FOCUS.
The Framer Module adheres to AT&T’s T1
standard, which is multiplexing 24 channels into a
single 1.544 Mbps data stream.
The module’s superframe synchronization is
essential for proper signaling between terminals.
One superframe comprises 24 synchronized
frames.
Currently, two versions exist for use in T1
systems, depending on your configuration require-
ments. The T1 framer is only for use with the
Maintenance Module version 3.x & 2.x (MV3 &
MV2). The TE1 framer is for use only with the
Maintenance Module version 5.x (MV5). The
framer must be used with the appropriate
Maintenance Module for proper operation of your
FOCUS system. Except for these configuration
requirements there are no significant differences
to the user between the two framer modules.
8.2.2 Framers Used in E1 Systems
(E1, TE1)
The Framer Module is an essential component in
a FOCUS chassis. It forms the vital link in the
network by providing the E1 multiplexer, which is
the standard communication protocol for FOCUS.
The Framer Module adheres to the CCITT E1
standard, which is multiplexing 30 channels into a
single 2.048 Mbps data stream.
The module’s multi-frame synchronization is
essential for proper signaling between terminals.
One frame comprises 16 synchronized frames.
Currently, two versions exist for use in E1
systems, depending on your configuration require-
ments. The E1 framer is only for use with the
Maintenance Module version 4.x (MV4). The TE1
framer is for use only with the Maintenance
Module version 5.x (MV5). The framer must be
used with the appropriate Maintenance Module
Frame ESF - T1 only
Format
Indicators Status LED
Loop back north or south
Loop back east or west
Framer synchronization lost
Blue alarm
RAI alarm
Synchronization lost in sync
direction
Functions Provides 24-channel T1
framing
Supports up to 4 T1 ports
Can supply time sync source
as the system master
Can act as slave, synchroni-
zing on either XCVR 1-1,
1-2, 2-1, or 2-2 incoming
data streams (T1 can only
sync to X1-1 or X2-1
Table 8–1. T1 Framer Specifications.
(T1 Systems Only, for use with MV2, MV3)