2-2 Installation
PRISM 3021
Configuration Switch S1
Switch S1 (Figure 2-2) is used to set the configuration
parameters listed in the following paragraphs.
Factory default settings are underlined through-
out this manual.
N
ETWORK
F
RAMING
Position S1-1 is used to select Channel Associated Signaling
(CAS) network framing or Common Channel Signaling
(CCS) network framing as shown in Table 2-A.
CRC4 M
ODE
Position S1-2 is used to enable or disable CRC4 as shown in
Table 2-B.
N
ETWORK
L
INE
C
ODE
Position S1-3 selects High-Density Bipolar of order 3
(HDB3) line code or Alternate Mark Inversion (AMI) line
code as shown in Table 2-C. HDB3 provides clear channel
capability.
T
IMING
S
OURCE
Positions S1-4 and S1-5 are used to select the source of unit
clocking as shown in Table 2-D. Deriving timing from the
network is the most common timing source for most applica-
tions. The unit may also be clocked from its internal oscilla-
tor; from equipment attached to the DTE; or from equipment
attached to the E1-DTE option card.
K
EEP
A
LIVE
F
RAMED
AND
U
NFRAMED
O
NES
Position S1-6 selects keep alive framed and unframed ones
as shown in Table 2-E. Keep alive is generated when the
unit detects LOS or OOF.
Table 2 -A Network Framing
Functions
S1-1
Network Framing CAS
Down
Network Framing CCS
Up
Table 2-B CRC4 Mode
Functions
S1-2
CRC4 enabled
Down
CRC4 disabled
Up
Switch S1
8
1 2 3 4 5 6 7
Switch S2
8
1 2 3 4 5 6 7
Switch S3
8
1 2 3 4 5 6 7
Switch S4
5
1 2 3 4
Figure 2-1 Top-Edge View of the PRISM 3021
7
6
5
4
3
2
1
Do
wn
Up
8
Network
CRC4
Network
Data
No
rmal
Pro
g
ram
Fra
m
ing
Mo
de
Fla
sh
o
r In
v
erted
K
e
ep Al
iv
e F
rame
d
an
d
Un
fr
a
m
ed
On
es
Lin
e Cod
e
Ti
m
in
g
So
urc
e
Ti
m
in
g
So
urc
e
Figure 2-2 Switch S1
Table 2 -C Network Line Code
Network Line Code
S1-3
HDB3
Down
AMI
Up
Table 2 -D Timing Source
Timing Source
S1-4
S1-5
Network
Down
Down
Internal
Down
Up
E1 DTE
Up
Down
DTE or External
Up
Up
Table 2-E Keep Alive Framed and Unframed Ones
Mode
S1-6
Keep Alive Unframed Ones
Down
Keep Alive Framed Ones
Up
