á
XRT72L56
SIX CHANNEL DS3/E3 FRAMER IC WITH HDLC CONTROLLER
PRELIMINARY
REV. P1.1.2
XI
Figure 112. Simple Illustration of the Transmit Overhead Data Input Interface block ........................ 271
T
ABLE
48: A L
ISTING
OF
THE
O
VERHEAD
BITS
WITHIN
THE
E3
FRAME
,
AND
THEIR
POTENTIAL
SOURCES
,
WITHIN
THE
XRT72L56 IC ................................................................................................................................ 272
T
ABLE
49: D
ESCRIPTION
OF
M
ETHOD
1 T
RANSMIT
O
VERHEAD
I
NPUT
I
NTERFACE
S
IGNALS
..................... 273
Figure 113. Illustration of the Terminal Equipment being interfaced to the Transmit Overhead Data Input
Interface (Method 1) ............................................................................................................................ 274
T
ABLE
50: T
HE
R
ELATIONSHIP
BETWEEN
THE
N
UMBER
OF
R
ISING
C
LOCK
E
DGES
IN
T
X
OHC
LK
, (
SINCE
T
X
O-
HF
RAME
WAS
LAST
SAMPLED
"H
IGH
")
TO
THE
E3 O
VERHEAD
B
IT
,
THAT
IS
BEING
PROCESSED
................. 275
Figure 114. Illustration of the signal that must occur between the Terminal Equipment and the XRT72L56
in order to configure the XRT72L56 to transmit a Yellow Alarm to the remote terminal equipment ... 276
T
ABLE
51: D
ESCRIPTION
OF
M
ETHOD
2 T
RANSMIT
O
VERHEAD
I
NPUT
I
NTERFACE
S
IGNALS
..................... 277
Figure 115. Illustration of the Terminal Equipment being interfaced to the Transmit Overhead Data Input
Interface (Method 2) ............................................................................................................................ 278
T
ABLE
52: 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
E3 O
VERHEAD
B
IT
,
THAT
IS
BEING
PROCESSED
BY
THE
XRT72L56 279
Figure 116. Behavior of Transmit Overhead Data Input Interface signals between the XRT72L56 and the
Terminal Equipment (for Method 2) .................................................................................................... 280
5.2.3 The Transmit E3 HDLC Controller ........................................................................................................ 280
Figure 117. LAPD Message Frame Format ....................................................................................... 281
T
ABLE
53: T
HE
LAPD M
ESSAGE
T
YPE
AND
THE
C
ORRESPONDING
VALUE
OF
THE
F
IRST
B
YTE
,
WITHIN
THE
I
NFOR
-
MATION
P
AYLOAD
.................................................................................................................................. 281
T
X
E3 C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
30) ............................................................................ 282
T
RANSMIT
E3 LAPD C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
33) ..................................................... 282
T
ABLE
54: R
ELATIONSHIP
BETWEEN
T
X
LAPD M
SG
L
ENGTH
AND
THE
LAPD M
ESSAGE
S
IZE
.................. 283
T
X
E3 LAPD C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
33) ................................................................. 283
T
RANSMIT
E3 LAPD C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
33) ..................................................... 283
T
X
E3 LAPD S
TATUS
AND
I
NTERRUPT
R
EGISTER
(A
DDRESS
= 0
X
34) ...................................................... 284
T
X
E3 LAPD S
TATUS
AND
I
NTERRUPT
R
EGISTER
(A
DDRESS
= 0
X
34) ...................................................... 284
Figure 118. Flow Chart Depicting how to use the LAPD Transmitter ................................................. 286
B
LOCK
I
NTERRUPT
E
NABLE
R
EGISTER
(A
DDRESS
= 0
X
04) ..................................................................... 287
5.2.4 The Transmit E3 Framer Block ............................................................................................................. 288
Figure 119. A Simple Illustration of the Transmit E3 Framer Block and the associated paths to other Func-
tional Blocks ........................................................................................................................................ 289
T
X
E3 C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
30) ............................................................................ 289
T
ABLE
55: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
2 (T
X
AIS E
NABLE
)
WITHIN
THE
T
X
E3 C
ONFIG
-
URATION
R
EGISTER
,
AND
THE
RESULTING
T
RANSMIT
E3 F
RAMER
B
LOCK
'
S
A
CTION
................................. 290
T
ABLE
56: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENTS
OF
B
IT
1 (T
X
LOS)
WITHIN
THE
T
X
E3 C
ONFIGURATION
R
EGISTER
,
AND
THE
RESULTING
T
RANSMIT
E3 F
RAMER
B
LOCK
'
S
A
CTION
............................................... 290
T
X
E3 C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
30) ............................................................................ 290
T
X
E3 S
ERVICE
B
ITS
R
EGISTER
(A
DDRESS
= 0
X
35) ................................................................................ 291
T
X
E3 C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
30) ............................................................................ 291
T
X
E3 C
ONFIGURATION
R
EGISTER
(A
DDRESS
= 0
X
30) ............................................................................ 292
T
X
E3 FAS E
RROR
M
ASK
R
EGISTER
- 0 (A
DDRESS
= 0
X
48) ................................................................... 292
T
X
E3 FAS E
RROR
M
ASK
R
EGISTER
- 1 (A
DDRESS
= 0
X
49) ................................................................... 292
T
X
E3 BIP-4 E
RROR
M
ASK
R
EGISTER
(A
DDRESS
= 0
X
4A) ...................................................................... 293
5.2.5 The Transmit E3 Line Interface Block ................................................................................................... 293
Figure 120. Approach to Interfacing the XRT72L56 Framer IC to the XRT73L03 DS3/E3/STS-1 LIU 293
Figure 121. A Simple Illustration of the Transmit E3 LIU Interface block ........................................... 294
Figure 122. The Behavior of TxPOS and TxNEG signals during data transmission while the Transmit DS3
LIU Interface is operating in the Unipolar Mode .................................................................................. 295
I/O C
ONTROL
R
EGISTER
(A
DDRESS
= 0
X
01) .......................................................................................... 295
T
ABLE
57: T
HE
R
ELATIONSHIP
BETWEEN
THE
CONTENT
OF
B
IT
3 (U
NIPOLAR
/B
IPOLAR
*)
WITHIN
THE
UNI I/O C
ON
-
TROL
R
EGISTER
AND
THE
T
RANSMIT
E3 F
RAMER
L
INE
I
NTERFACE
O
UTPUT
M
ODE
.................................. 295
Figure 123. Illustration of AMI Line Code ........................................................................................... 296
Figure 124. Illustration of two examples of HDB3 Encoding .............................................................. 297