MTC-20172-PC AMI Semiconductor, Inc., MTC-20172-PC Datasheet - Page 36

• Manufacturer Part Number: MTC-20172-PC
• Description: S Interface Circuit for ISDN (SIC)
• Manufacturer: AMI Semiconductor, Inc.

5.1.11 Transmitted Frames:
Depending on the activation state of
the interface, the MTC-20172 SIC can
transmit different signals called INFO
0, 1, 2, 3, and 4. Moreover, two test
signals are defined
5.1.11.1 Details on Downlink
Frames: Network to Terminal
The downlink Frames transmitted by
upstream devices contain an E-bit.
During INFO4, the E-bit is the echoed
D-channel bit received from the
downstream devices, see 5.6. This D-
echo-channel is used for the D-channel
access procedure, see 5.7.
Two L-bits are used for DC-balancing,
after the F-bit and the last bit the
frame. In downlink direction some
special bits are used, see Figure 5.1:
- A-bit used for activation (A=1 for
- S-bit coded as binary zero, if no
- N-bit coded as N = .NOT. FA
- M-bit at binary zero, except when
- FA-bit, additional flag (bin. zero),
Without multiframing active, S, FA, M
bits are binary zeros. Multiframing is
allowed to be active during INFO2
and INFO4, and influences the S, FA,
M bits as described under 5.9.
INFO4, A=0 for INFO2);
multiframing active;
(applies to INFO2 and INFO4);
multiframing ( 5.9);
except when multiframe.
5.1.11.2 Uplink Frames:
Terminal to Network
The INFO3 frame transmitted at
terminal-side consists of several
groups of bits, each of them DC-
balanced by an adjacent symmetry-bit
L.
See Figure 5.1.
The uplink D-channel requires an
access protocol, detailed in 5.7.
Signals from network
to terminal
INFO0
INFO2
INFO4
TEST1
TEST2
The B-channel and D-channel are transparently transmitted on the S-bus.
When idle, these channels are all binary 1.
No signal, open circuit
Frame with all bits of
B, D, and E-Echo channels,
and a bit at binary zero,
FA, M, S, N and L bits
six ONEs follow the coding
rules of 5.1.11.1
Frame with operational
data on B, D, and E-Echo
channels. Bit A set to
binary ONE. FA, M, S, N, L
bits follow the coding rules
rules of 5.1.11.1
Send Single Zeros (SSZ),
AMI marks, 250 µs distance
forced via pin (NT) or C/I
Send Continuous Zeros
(SCZ), alternating marks,
marks forced via pin
(NT) or C/I
26
MTC-20172
Data Sheet & Reference Manual
Rev. 1.1 February 1997
Signals from terminal
to network
INFO0 No signal, open circuit
INFO1 Continuous signal with
INFO3 Synchronized frames with
TEST1 Send Single Zeros (SSZ),
TEST2 Send Continuous Zeros
Downlink multiframing influences the
FA-bit in uplink (Q-channel): If the
MTC-20172 SIC receives the FA-bit
as binary 0 (electrical mark), it will
always answers with binary 0. If the
MTC-20172 SIC sees the FA-bit as
binary 1 it answers with binary 1,
when multiframing is not active.
When using multiframing the FA-bit is
coded as described in section 5.9.
the following pattern :
positive zero,
negative ZERO,
operational data on B, D
channels. FA and L bits
according to normal coding
of 5.1.11.2
AMI marks, 250 µs distance
forced via pin (NT) or C/I
(SCZ),alternating
forced via pin (NT) or C/I