Installation guide

Making External Connections to Cisco 4000 Series Routers 4-65
Network Connection Considerations
Figure 4-17 X.21 Adapter Cable Connectors, Network End
EIA-530 Connections
EIA-530, which supports balanced transmission, provides the increased functionality,
speed, and distance of EIA/TIA-449 on the smaller, DB-25 connector used for
EIA/TIA-232, instead of the 37-pin connectors used for EIA/TIA-449. Like EIA/TIA-449,
EIA-530 refers to the electrical specifications of EIA/TIA-422 and EIA/TIA-423. Although
the specification recommends a maximum speed of 2 Mbps, EIA-530 is used successfully
at 4 Mbps or faster speeds over short distances.
The EIA-530 adapter cable is available in DTE mode only. The network end of the EIA-530
adapter cable is a standard DB-25 plug commonly used for EIA/TIA-232 connections.
Figure 4-18 shows the DB-25 connector at the network end of the adapter cable.
Figure 4-18 EIA-530 Adapter Cable Connector, Network End
Interference Considerations
When wires are run for any significant distance in an electromagnetic field, interference can
occur between the field and the signals on the wires. This fact has two implications for the
construction of terminal plant wiring:
1
8
15
9
DCE
DTE
H1346a
DTE
H1615a