Raisecom RC802-240B User manual - page 8
Raisecom Technology Co., Ltd
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sent through the optical link, so that they are accurate only when the optical receiving is
working in good condition.
4.2. DIP-switches Configuration
4.2.1. Dip-switches for E1 Interface Impedance
There are 8 groups of 4-bit dip-switches, SW1 to SW8. These switches
cannot be managed by network management software, so they must be
set manually.
Definition as shown below
1
st
2
nd
3
rd
4
th
1
st
2
nd
3
rd
4
th
ON
ON
ON
OFF
Or OFF
OFF
OFF
ON
75Ω unbalanced signal effective
120Ω balanced signal effective
As shown in figure above, the default status is set as “75Ω unbalanced signal BNC
interface effective”.
• When adopting 75 Ohm unbalanced signal, it is required to plug a DB37 to 8 CC3
coaxial adapter, which is of CC4B-8G type. This adapter can convert DB37 connector
to 8 CC3 coaxial connectors, for input and output of 4 E1 channels.
• When adopting 120 Ohm balanced signal, it is required to first set the dip-switches as
per the above tables. 37-pin connector shall be used to connect the twisted-pair cables
for DB37 connector. Please refer to Appendix A for details of sequence of twisted-pair
and cable making.
4.2.2. DIP-switch for Function Configuration
There is a 6-bit dip-switch SW10 on the PCB.
• 1
st
~ 4
th
: Loop-back control
1
st
bit
2
nd
bit
3
rd
bit
4
th
bit
Loop-back
OFF OFF OFF OFF No
loop-back
OFF OFF OFF ON 1
st
E1
OFF OFF ON OFF 2
nd
E1
OFF OFF ON ON 3
rd
E1
OFF ON OFF OFF 4
th
E1
OFF ON OFF ON 5
th
E1
OFF ON ON OFF 6
th
E1
OFF ON ON ON 7
th
E1
ON OFF OFF OFF 8
th
E1
ON ON ON ON All
E1
links
Note: Only two test method can be set: single E1 channel loop-back or all E1 channels
loop-back. When single E1 channel loop-back is testing, the other channels are working
normally without disturbance.
The network management software can send out the loop-back enable/disable command,
and they have high priority to the settings by hardware.
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