Black Box LR5200A-R2, LR5100A-T manual Changing the Termination Straps on the ISDN S/T Interface

Servicing Information

Changing the Termination Straps on the ISDN S/T Interface

The ISDN S/T link interface module has two configurable straps that control whether the ISDN LINE is set to terminated or unterminated.

Jumper straps W5 and W6 are factory installed to configure the module as TERMINATED. The TERMINATED position is used when the bridge/router is the only ISDN device connected to the ISDN circuit.

Removing the W5 and W6 straps sets the module to UNTERMINATED. This allows this bridge/router to be part of a daisy-chain connection to the ISDN circuit by using the ISDN AUX connector.

Figure C-5 ISDN S/T Module Termination setting jumpers

Connecting to the ISDN-U Link Module

The connection to the central office is made with the RJ45 connector on the panel of the U Module. Pins 4 and 5 are used for the connection. These pins are polarity insensitive.

The Ferrite module included with the ISDN U Module must be installed on the cable that is connected to the ISDN U Module. The Ferrite module must be installed approximately two inches from the RJ45 connector at the bridge/router end of the cable. The cable must pass through the Ferrite module twice with a Single loop around the Ferrite module.

Figure C-6 Ferrite Module Installed on the Cable.

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