5. IT-7301-PC Application
5.1 E1 configuration
The device support two physical match impedance of the E1 interface, which can automatics 120ohm
balanced twisted-pair and 75-ohm non-balanced coaxial cable interface. Users can select the appropriate
interface to connection dispense with any operation.
5.2 Connection the Twisted Pair (120 ohm) to the G.703 Network
As shown, 1 and 2 are sending lines, 4 and 5 are receiving lines.
Line Sequence of Balanced Twisted-Pair at E1 Interface RJ45
Attention: In E1 twisted-pair standard, 1 and 2 are defined as sending lines, 4 and 5 as receiving lines.
5.3 Sittings of Switch and Jumper
Independent device has totally 5 setting switches, with S5 located on the rear panel and S1~S4 under the
bottom cover. The user can easily make settings without the need to open the cover.
5.3.1 Clock setting
E1 interface timing (S5.1=ON/OFF, S5.2=OFF): the sending timing is E1 port timing, and the received data,
after buffering, is synchronized with E1 port timing.
Optic interface receiving timing (optic interface originated from the clock, S5.1=OFF，S5.2=ON): the sending
timing is optic interface receiving timing, and the received data, after buffering, is synchronized with optic
interface receiving timing. Under this timing mode, local time slot setting can automatically track the opposite
time slot setting.
Local main timing (S5.1=ON, S5.2=ON): the sending timing is of local crystal oscillation, and the received
data, after buffering, is synchronized with local timing.
5.3.2 Settings of loop back test and pseudo-random code test
S5.5～S5.8 of coded switch S5 are used for setting the loop back test and pseudo-random code test. S5.5 is
local loop back control （LLOOP）and optic interface is directly looped back to E1 interface. “OFF” indicates
normal operation; “ON” indicates local loop back test. The default is “OFF”. It is used for testing whether local
device is in normal operation.
1
2
3
4
5
6
7
8
1. TX+ Positive end of data transmission
2. TX- Negative end of data transmission
3. Idel
4. RX+ Positive end of data reception
5. RX- Negative end of data reception
6. Idel
7. Idel
8. Idel
