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Preparing for Installation 2-17

Network Connection Considerations

Figure 2-15 V.35 Adapter Cable Connectors, Network End

X.21 Connections

The X.21 interface uses a 15-pin connection for balanced circuits and is commonly used in the

United Kingdom to connect public data networks. X.21 relocates some of the logic functions to the

DTE and DCE interfaces and, as a result, requires fewer circuits and a smaller connector than

EIA/TIA-232.

The network end of the X.21 adapter cable is a standard DB-15 connector. (See Figure 2-16.)

X.21 cables are available as either DTE (DB-15 plug) or DCE (DB-15 receptacle).

Figure 2-16 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 2-17 shows

the DB-25 connector at the network end of the adapter cable.

Figure 2-17 EIA-530 Adapter Cable Connector, Network End

H1616a

DTE

DCE

DTE

H1346a

DTE

H1615a

Cisco EF4116 User Manual

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