Troubleshooting guide

Section 1, System Description - System Connectivity
61186003L1-1D 1-19
SYSTEM CONNECTIVITY
The shelf backplane contains Input/Output (I/O) connectors, control and signal routing,
power input and ground, plus the interconnections between BITS clock cards, MUX cards,
and the SCU.
Figure 1-7 shows the MX2820 Multiplexer system with management and network interfaces.
Figure 1-7. MX2820 Multiplexer System Configuration
Power Connections
The MX2820 system is designed to accommodate redundant power configurations. The
system operates with either individual supply or both supplies functioning. Dual terminals for
DC Voltage (–48 or ±24 VDC) and return are provided.
A Barrier strip connector on the shelf backplane provides the power connections for power
and the frame ground. The frame ground connection is routed to the metal MX2820 chassis.
Timing
The MX2820 system operates in local, loop (network), or external (BITS) timing mode. In the
local timing mode, an onboard timing reference is provided. In the loop timing mode, the MUX
modules synchronize with the received DS3 or STS-1 signal. Because the multiplexing/de-
multiplexing process is asynchronous, each DS1 channel maintains its own Transmit and
Receive timing.
External timing mode only applies to STS-1 MUX modules and requires an MX2820 Clock
module. The STS-1 MUX module synchronizes its STS-1 transmit signal to the DS1 BITS clock
signal received at the Clock module.
SNMP Management
Station
MX2820
Ethernet
LAN
To
Subtended
Shelves
RS232
RS485
10BaseT
Built-in
PAD
DS3
STS-1
DSX-1 (T1/E1)
NMA Mainframe
X.25
Network
Network
Network
Network
VT100
Terminal
C
R
A
F
T
1186003
SCU
ACO
ALM
ACT
CLKB
CLK A
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
7B
1186000
BLANK
1186000
BLANK
MX 2820
1186001L1
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
7B
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
7A
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
6B
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
6A
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
5B
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
5A
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
4B
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
4A
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
3B
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
3A
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
2B
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
2A
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
1B
1186002
MUX
ALM
ACT
TEST
STAT
TEST
STAT
DS1
DS3
1A