MT8930C
0 - 1 Km
NT
T
R
T
R
TE
NT is operating in adaptive timing
TR is the line termination resistor = 100
Ω
Figure 8 - Point-to-Point Configuration
100 m for 75
Ω
impedance cable and 200 m for 150
Ω
impedance cable
100 - 200 m
NT
T
R
T
0 - 10 m R
TE
TE
TE
TE
TE
TE
TE
TE
NT is operating in fixed timing
TR is the line termination resistor = 100
Ω
Fiure 9 - Short Passive Bus Configuration, up to 8 TEs can be supported
0-500 m
NT
T
R
0-50 m
0 - 10 m
T
R
TE
TE
TE
TE
TE
TE
TE
TE
NT is operating in adaptive timing
TR is the line termination resistor = 100
Ω
Figure 10 - Extended Passive Bus Configuration, up to 8 TEs can be supported
TEs . All NT devices connected into the star will
receive the information transmitted by all TEs on all
branches of the star, exactly as if they were on the
same physical S-Bus.
All NTs in the star
configuration must be operating in fixed timing mode.
Refer to the description of the star configuration in
the ST-BUS section.
The SNIC has one last mode of operation called the
NT slave mode. This has the effect of operating the
SNIC in network termination mode (CK/NT pin = 1)
but having the frame structure and registers
description defined by the TE mode. This can be
used where multiple subscriber loops must carry a
fixed phase relation between each line. A typical
situation is when the system is trying to synchronize
two nodes of a synchronous network. This allows
multiple TEs to share a common ST-BUS timebase.
The synchronization of the loops is established by
using the clock signals produced by a local TE as an
input timing source to the NT slave.
Adaptive Timing Operation
On power-up or after a reset, the SNIC in NT mode is
set to operate in fixed timing. To switch to adaptive
timing, the user should:
1) set the DR bit to 1
2) set the Timing bit to 1 in the C-channel
Control Register
3) wait for 100 ms period
4) proceed in using the AR and DR bits as
desired
Switching from adaptive timing mode is completed
by resetting the Timing bit.
9-43
MITEL [ MITEL NETWORKS CORPORATION ]
