Specifications

C-18
Cisco 7100 Series VPN Router Installation and Configuration Guide
78-6341-03
Appendix C Cable Specifications
Cisco 7120-T3, Cisco 7120-E3, Cisco 7140-2T3, and Cisco 7140-2E3 Cables
Cisco 7120-T3, Cisco 7120-E3, Cisco 7140-2T3, and
Cisco 7140-2E3 Cables
The T3 or E3 serial interface cable on the Cisco 7120 and Cisco 7140 series, which is a 75-ohm coaxial
cable, is used to connect your router to a T3 or E3 serial network. Serial cables conform to EIA/TIA-612
and EIA/TIA-613 specifications. The serial ports are considered to be DTE devices.
The T3 or E3 serial port has two connectors (receive and transmit) where you connect the Cisco 75-ohm
coaxial cable. The 75-ohm coaxial cable (Cisco product number CAB-ATM-DS3/E3), is available only
from Cisco Systems; it is not available from outside commercial cable vendors.
Figure C-10 shows the Cisco 75-ohm coaxial cable, which is available in 10-foot (3.05-meter) lengths
only. The typical maximum distance between stations for T3 or E3 transmissions is 1300 feet (396
meters).
Note For E3 (75-ohm) connections, you must have ferrite beads on the 75-ohm coaxial cable and
electromagnetic interference (EMI) decoupling clips on the receiver end of the cable (see Figure C-10)
if compliance with European certification standards for emission control is required
(EN55022/CISPR22 Class B for radiated emission levels).
Figure C-10 T3 and E3 Serial Port Adapter Cables
The T3 and E3 ports support several types of integrated data service units (DSUs). Table C-17 lists the
features supported.
X
M
TRR
C
V
R
X
M
T
RR
C
V
R
E
N
R
C
L
K
F
E
R
F
R
L
A
I
S
O
O
F
L
L
R
C
L
K
F
E
R
F
R
L
A
I
S
O
O
F
L
L
5
I
To T3 network
equipment
Ferrite bead
22139
75-ohm coaxial cabling
BNC plugBNC plug
EMI decoupler clip
Table C-17 Feature Compatibilities of T3 and E3 Serial Port DSUs
Device Full Rate Scrambling Subrate MDL
1
T3 DSU
DL3100 Yes Yes Yes No
Kentrox Yes Yes
2
Yes
2
No
Larscom Yes Yes Yes No
E3 DSU