MT8930C
Signals from NT to TE
Info0
No Signal
Info0
Info1
Signals from TE to NT
No Signal
Continuous Signal of +‘0’, -‘0’
and six ‘1’s
(1)
Where: BA
(2)
= Bus Activity
DR = Deactivation Request
AR = Activation Request
Sync
(2)
= Frame Sync Signal
A = Activation bit
Time out = 32 ms Timer Signal
Note 1: signal is not timebase locked to NT.
Info3
Info4
Valid frame with data in B,
D, D-echo channels. Bit A is
set to 1.
Valid frame with data in B & D
Bits
Note 2: Sync/BA bit of the Status Register
is configured as Sync bit when
AR = 1 and DR = 0, or as BA bit
when AR = 0 or DR = 1. A change in
the state of the AR and/or DR bits
will cause a change in the function
of the Sync/BA bit in the following
ST-BUS frame.
Info2
Valid frame structure with
all B, D, D-echo and A bits
set to ‘0’
TE State Activation Diagram
DR = 1
AR = 1
BA = 0
Deactivated
send Info0
Sync = 1
DR = 1
DR = 1
Activated
send Info3
A=1&
Sync = 1
Sync = 0
A=0
BA = 0
NT State Activation Diagram
BA = 1
AR = 1
DR = 1
Pending
Activation
send Info2
Sync = 1
DR = 1
Sync = 0
Activated
send Info4
Pending
Deactivation
Send Info0
Deactivated
send Info0
Time out
BA =0
Synchronized
send Info3 if Sync = 1
send Info0 if Sync = 0
Activation Request
send Info1 if BA = 0
send Info0 if BA = 1
Sync = 1
AR = 1
Figure 7 - Link Activation Protocol, State Diagram
Line Wiring Configuration
For an NT SNIC in fixed timing mode, the VCO and
Rx filters/peak detectors are disabled and the
threshold voltage is fixed. However, for a TE SNIC or
The MT8930C can interface to any of the three
an NT SNIC (in adaptive timing mode), the VCO and
wiring configurations which are specified by CCITT
Rx filters/peak detectors are enabled.
In this
Recommendation I.430 and ANSI T1.605 (refer to
manner, the device can compensate for variable
Figs. 8 to 10). These consist of a point-to-point or
round trip delays and line attenuation using a
one of the two point-to-multipoint configurations (i.e.,
threshold voltage set to a fixed percentage of the
short passive bus or the extended passive bus). The
pulse peak amplitude.
selection of line configurations is performed using
the timing bit (B4 of NT Mode Control Register).
Another operation can be implemented using the
SNIC in the star configuration as shown in Figure 14.
For the short passive bus, TE devices are connected
This mode allows multiple NTs, with physically
at random points along the cable. However, for the
independent S-Busses, to share a common input
extended passive bus all connection points are
source and transfer information down the S-Bus to all
grouped at the far end of the cable from the NT.
9-42
MITEL [ MITEL NETWORKS CORPORATION ]
