User Manual
Airbridge cBTS3612 CDMA Base Station
System Description
2 Hardware Architecture
2-61
DB37
DB25
DB25
16 E1 lightning
protection units
128mm
128mm
Fixing hole
Ф
3.5
PGND
Ф
10
Out from the
cabinet
(4 pairs of
E1s)
Into the
cabinet
(8 pairs of
E1s)
10mm
6mm
6mm
5mm
Out from the
cabinet
(4 pairs of
E1s)
Figure 2-31
Physical appearance of BESP
E1 lightning protection unit has two inbound lines connected with DB25, two
outbound lines connected with DB37, and one PGND. Here PGNDs of all lightning
protection units can be interconnected. DB37 is male connector and DB25 is female
connector, with 8 pairs of shielded E1 cables connected. 75 Ù and 120Ù impedance
match is provided with the cables. The principle of lightning protection units is as
shown in Figure 2-32.