
á
XRT72L50
SINGLE CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
REV. 1.2.1
V
Figure 40. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 5 (Nibble-
Parallel/Local-Timed/Frame-Slave) Operation ............................................................................................. 147
4.2.1.6 Mode 6 - The Nibble-Parallel/TxInClk/Frame-Master Interface Mode Behavior of the XRT72L50 148
Figure 41. Behavior of the Terminal Interface signals between the XRT72L50 and the Terminal Equipment (DS3 Mode 5
Operation) .................................................................................................................................................... 148
Figure 42. The Terminal Equipment being interfaced to the Transmit Payload Data Input Interface block for Mode 6 (Nibble-
Parallel/Local-Timed/Frame-Master) Operation ........................................................................................... 149
Figure 43. Behavior of the Terminal Interface signals between the XRT72L50 and the Terminal Equipment (DS3 Mode 6
Operation) .................................................................................................................................................... 150
4.2.2 The Transmit Overhead Data Input Interface ........................................................................................ 151
Figure 44. The Transmit Overhead Data Input Interface block .................................................................................... 151
4.2.2.1 Method 1 - Using the TxOHClk Clock Signal .............................................................................. 152
T
ABLE
16: O
VERHEAD
BITS
WITHIN
THE
DS3
FRAME
AND
THEIR
POTENTIAL
SOURCES
WITHIN
THE
XRT72L50 IC ............. 152
T
ABLE
17: D
ESCRIPTION
OF
M
ETHOD
1 T
RANSMIT
O
VERHEAD
I
NPUT
I
NTERFACE
S
IGNALS
............................................... 153
Figure 45. The Terminal Equipment being interfaced to the Transmit Overhead Data Input Interface (Method 1) ..... 154
T
ABLE
18: T
HE
R
ELATIONSHIP
BETWEEN
THE
N
UMBER
OF
R
ISING
C
LOCK
E
DGES
IN
T
X
OHC
LK
SINCE
T
X
OHF
RAME
WAS
LAST
SAMPLED
"H
IGH
"
TO
THE
DS3 O
VERHEAD
B
IT
THAT
IS
BEING
PROCESSED
....................................................... 154
Figure 46. Illustration of the signal that must occur between the Terminal Equipment and the XRT72L50, n order to configure
the XRT72L50 to transmit a Yellow Alarm to the remote terminal equipment ............................................. 157
4.2.2.2 Method 2 - Using the TxInClk and TxOHEnable Signals ............................................................ 158
T
ABLE
19: D
ESCRIPTION
OF
M
ETHOD
2 T
RANSMIT
O
VERHEAD
I
NPUT
I
NTERFACE
S
IGNALS
............................................... 158
Figure 47. The Terminal Equipment being interfaced to the Transmit Overhead Data Input Interface (Method 2) ..... 159
T
ABLE
20: T
HE
R
ELATIONSHIP
BETWEEN
THE
N
UMBER
OF
T
X
OHE
NABLE
PULSES
SINCE
THE
LAST
OCCURRENCE
OF
THE
T
X
OHF
RAME
PULSE
,
TO
THE
DS3 O
VERHEAD
B
IT
THAT
IS
BEING
PROCESSED
BY
THE
XRT72L50 ................... 159
4.2.3 The Transmit DS3 HDLC Controller ...................................................................................................... 162
4.2.3.1 Bit-Oriented Signaling (or FEAC Message) processing via the Transmit DS3 HDLC Controller. 162
Figure 48. Behavior of Transmit Overhead Data Input Interface signals between the XRT72L50 and the Terminal Equipment
(for Method 2) .............................................................................................................................................. 162
4.2.3.2 Message-Oriented Signaling (e.g., LAP-D) processing via the Transmit DS3 HDLC Controller 164
Figure 49. A Flow Chart depicting how to transmit a FEAC Message via the FEAC Transmitter ............................... 164
Figure 50. LAPD Message Frame Format .................................................................................................................. 165
T
ABLE
21: T
HE
LAPD M
ESSAGE
T
YPE
AND
THE
C
ORRESPONDING
VALUE
OF
THE
F
IRST
B
YTE
WITHIN
THE
I
NFORMATION
P
AYLOAD
166
T
ABLE
22: R
ELATIONSHIP
BETWEEN
T
X
LAPD M
SG
L
ENGTH
AND
THE
LAPD M
ESSAGE
S
IZE
........................................... 166
T
ABLE
23: R
ELATIONSHIP
BETWEEN
T
X
LAPD M
SG
L
ENGTH
AND
THE
LAPD M
ESSAGE
S
IZE
........................................... 167
Figure 51. Flow Chart depict how to use the LAPD Transmitter ................................................................................. 169
4.2.4 The Transmit DS3 Framer Block ........................................................................................................... 170
4.2.4.1 Brief Description of the Transmit DS3 Framer ............................................................................ 170
4.2.4.2 Detailed Functional Description of the Transmit DS3 Framer Block ........................................... 171
Figure 52. The Transmit DS3 Framer Block and the associated paths to other Functional Blocks ............................. 172
T
ABLE
24: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
7 (T
X
Y
ELLOW
A
LARM
)
WITHIN
THE
T
X
DS3 C
ONFIGURATION
R
EGISTER
,
AND
THE
RESULTING
T
RANSMIT
DS3 F
RAMER
B
LOCK
'
S
A
CTION
...................................................... 173
T
ABLE
25: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
6 (T
X
X-B
ITS
)
WITHIN
THE
T
X
DS3 C
ONFIGURATION
R
EGISTER
,
AND
THE
RESULTING
T
RANSMIT
DS3 F
RAMER
B
LOCK
'
S
A
CTION
.............................................................................. 173
T
ABLE
26: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
5 (T
X
I
DLE
)
WITHIN
THE
T
X
DS3 C
ONFIGURATION
R
EGISTER
,
AND
THE
RESULTING
T
RANSMIT
DS3 F
RAMER
A
CTION
............................................................................................ 174
T
ABLE
27: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
4 (T
X
AIS P
ATTERN
)
WITHIN
THE
T
X
DS3 C
ONFIGURATION
R
EGISTER
,
AND
THE
RESULTING
T
RANSMIT
DS3 F
RAMER
B
LOCK
'
S
A
CTION
...................................................... 174
T
ABLE
28: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
3 (T
X
LOS)
WITHIN
THE
T
X
DS3 C
ONFIGURATION
R
EGISTER
,
AND
THE
RESULTING
T
RANSMIT
DS3 F
RAMER
B
LOCK
'
S
A
CTION
.............................................................................. 175
4.2.5 The Transmit DS3 Line Interface Block ................................................................................................. 177
Figure 53. Interfacing the XRT72L50 Framer IC to the XRT73L00 DS3/E3/STS-1 LIU .............................................. 178
Figure 54. The Transmit DS3 LIU Interface block ....................................................................................................... 178
4.2.5.1 Selecting the various Line Codes ............................................................................................... 179
Figure 55. The Behavior of TxPOS and TxNEG signals during data transmission while the Transmit DS3 LIU Interface is
operating in the Unipolar Mode ................................................................................................................... 179
T
ABLE
29: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENT
OF
B
IT
3 (U
NIPOLAR
/B
IPOLAR
)
WITHIN
THE
UNI I/O C
ONTROL
R
EGISTER
AND
THE
T
RANSMIT
DS3 F
RAMER
L
INE
I
NTERFACE
O
UTPUT
M
ODE
.................................................................. 180
Figure 56. Illustration of AMI Line Code ..................................................................................................................... 180
4.2.5.2 TxLineClk Clock Edge Selection ................................................................................................. 181
Figure 57. Illustration of two examples of B3ZS Encoding ......................................................................................... 181
T
ABLE
30: T
HE
R
ELATIONSHIP
BETWEEN
B
IT
4 (AMI/B3ZS*)
WITHIN
THE
I/O C
ONTROL
R
EGISTER
AND
THE
B
IPOLAR
L
INE
C
ODE
THAT
IS
OUTPUT
BY
THE
T
RANSMIT
DS3 LIU I
NTERFACE
B
LOCK
...................................................................... 181
T
ABLE
31: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
2 (T
X
L
INE
C
LK
I
NV
)
WITHIN
THE
I/O C
ONTROL
R
EGISTER
AND
THE