Data Sheet
103
Rev. 1.2, 2006-01-26
QuadFALC
TM
PEF 22554 E
Functional Description E1/T1/J1
3.5
Line Coding
The QuadFALC
TM supports both optical and analog ternary/digital dual rail input/output network signals.
Supported for the optical interface (separate clock and data lines) are:
In E1 mode NRZ and CMI (Code Mark Inversion or known as 1T2B)
In T1/J1 mode NRZ.
Supported for the analog ternary or digital dual rail interface (clock is embedded in data) are
In E1 mode Alternate Mark Inversion (AMI) and High Density Bipolar of order 3 (HDB3)
In T1/J1 mode AMI and Bipolar with 8 Zero Substitution (B8ZS).
An overview of the line coding is given in Table 14.
The receiver and transmitter can be programmed with different line coding, although they are generally
programmed the same.
In T1/J1 an alternative scheme is called bit 7 zero code substitution (B7ZCS). If a DS0 channel contains 8 zeros
(00
H), then the code 02H is substitude into the data stream to assure the minimum 1“s density. At the receiving
end it is not possible to distinguish whether the received byte is actually 02
H or substituded for 00H. Therefore, data
can be corrupted at the transmission end by virtue of this substitution technique. B7ZCS is not suitable for data
transmission applications.
Table 13
Conditions for a PLL Reset
Reset Pin
GCM2.VFREQ_EN
Used Controller
Interface
A PLL reset is made if ...
Active
X (will be set to 1
B
by reset)
XAlways
Inactive
1
Asynchron
(Motorola or Intel)
If GCM5 or GCM6 are written and their values N or M
change
SPI or SCI
If pinstrapping values change
0
Asynchron
(Motorola or Intel)
Never
SPI or SCI
If pinstrapping values change
0 -> 1 or 1 -> 0
Asynchron
(Motorola or Intel)
If actual values of N or M in GCM5 or GCM6 are
different to internal settings of the “clocking fixed mode”
SPI or SCI
If pinstrap values are different to internal settings of the
“clocking fixed mode”; That is not allowed!
Table 14
Summary of Line Coding
Line Interface
LIM1.DRS
E1 Coding
FMR3.CMI T1 Coding
FMR0.RC
(1:0)
FMR0.XC
(1:0)
RX
TX
Optical NRZ
X
NRZ
X
NRZ
00
Optical CMI, single
line
X
1T2B/HDB3 1T2B/HDB3 0
SIC3.CMI:
with/without
B8ZS
precoding
01
1T2B
1
Ternary
0
AMI
X
AMI/ B7ZCS
clear
channel
10
Dual Rail
1
Ternary
0
AMI/HDB3
X
AMI/B8ZS
11
Dual Rail
1