American Telecom AM64/128A manual Interface Modules

AM64/128A User Manual Appendix B – Internal Link Settings

Interface Modules

X.21 Interface Module:

J1 – Circuit 103 Termination.

J2 - Circuit 113 Termination.

J1 - X.21 T (Transmit data) Circuit Termination – This link connects a 120 ohm load resistor across the T circuit position 1-3. This helps maintain signal rise times and minimises reflections at rates greater than 9.6 kbps over long lines. At lower rates and over short lines the termination resistor may be omitted, (link set position 1-2).

J2 – X.21 SEXT (External Signal Element Timing) Circuit Termination – This link connects a 120 ohm load resistor across the SEXT circuit in position 1-3. This helps maintain signal rise times and minimises reflections at rates greater than 9.6 kbps over long lines. At lower rates and over short lines the termination resistor may be omitted, (link set position 1-2).

V.35 Interface Module:

Removable link shown joining pins 1-2, to reverse connection of A and B wires to Circuit 113 move link to position 1-3.

J1 – V35 Circuit 113 (External Signal Element Timing) Input Polarity Selection – This aspect of the V35 interface may be implemented differently by different manufacturers. This link allows the authorised personnel to swap the polarity of the A and B wires of this differential input circuit. The factory default setting for this position 1-2.

V.36 Interface Module:

J1 – Circuit 103 Termination.

J2 – Circuit 113 Termination.

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