4.5 CONNECTING TO A DCE DEVICE

The rear interface cards on most interface modules are hard wired as DCE . Therefore, you must use a null modem cable when connecting to a modem, multiplexer or other DCE device. This cable should be of the shortest possible length--we recommend 6 feet or less. When purchasing or constructing a null modem interface cable, use the pin diagrams in Appendix C as a guide.

NOTE: Pin-out requirements for null modem applications vary between equipment manufacturers. If you have any questions about a specific installation, please contact Patton Electronics Technical Support.

4.6 CONNECTING THE E1 INTERFACE

The Network Line Interface is an eight position keyed modular jack configured as a RJ-48C. This interface will need to be configured to match the line parameters (i.e. framing, line coding, etc.) supplied by the central office.

 

1

RX Data (TIP)

 

From Network

 

2

RX Data (RING) }

1

 

3

(no connection)

 

 

2

 

 

3

4

TX Data (TIP)

}

To Network

4

5

TX Data (RING)

5

 

 

6

6

(no connection)

 

 

7

 

 

8

7

(no connection)

 

 

 

8

(no connection)

 

NOTE: If the

Figure 11. NetLink-E1™twisted pair line interface.

NetLink-E1™ is being used for private short range modem appli- cations, the twisted pair cable connected to its port will need to be a cross-over cable. See Appendix D for Interface pin assignments.

4.7 CONNECTING DUAL COAX BNC (75 OHM)

In addition to the 120 Ohm twisted pair connection, the Model 2701RC, when used with the 1001RCM11575 rear card, is equipped with dual female BNCs (TX and RX) for connection to a 75 ohm dual coax G.703 network interface.

5.0OPERATION

Once the NetLink-E1™ is installed and configured properly it is ready to place into operation. This section describes the function of the LED indicators, and the use of the loopback and pattern test modes.

5.1 LED DESCRIPTIONS

The NetLink-E1™ is equipped with nine LED indicators that monitor the status of communication. Figure 12 (below) shows the location of the LEDs on the NetLink-E1™ Series front panel.

Model 2701RC

Figure 12. Model 2701RC front panel, showing LED indicators.

TXD

When the unit sends a one, the TXD LED is

 

green. When it sends a zero, the TXD LED

 

is yellow. Moreover, the TXD LED is active

 

only in active DS0 channels. In inactive

 

channels, the TXD LED is off.

RXD

When the unit receives a one, the RXD LED

 

is green. When it receives a zero, the RXD

 

LED is yellow. Moreover, the RXD LED is

 

active only in active DS0 channels. In inac-

 

tive channels, the RXD LED is off.

LOS

The Loss of Sync LED lights when the unit

 

loses synchronization with the incoming sig-

 

nal. This may happen when there is a fram-

 

ing mismatch or a loss of signal. In

 

unframed mode, the LOS LED monitors the

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