Carrier Access 1750 Manual De Usuario

1. If a Building Integrated Timing Supply (BITS) clock will be used, an 

impedance matching adjustment may be required before installing an OC-12 
NIMs. BITS impedance matching jumpers are located on the NIM component 
side below the midplane connectors. They are labeled JMP1, JMP2, JMP3, 
and JMP4. The following settings are available.

JMP3, JMP4 in (default)

100 ohms 

JMP1, JMP2, JMP3, JMP4 in

75 ohms

All jumpers out

No termination

BITS input is provided to the RJ48C BITS connector on the corresponding 
NIM IOM (see “BITS Interface Connections” on page

). 

OC-12 NIMs go in slots A and B. (Both optical NIMs must be 

identical.) The NIM in slot B is the Working unit and the NIM in slot A is the 
Protection unit. 

2. Place the Working NIM in slot B from the front so that it slides smoothly in the 

top and bottom card guides and the card connector aligns with the midplane 
connector. 

3. Firmly press the NIM into the chassis until the connectors seat against each 

other completely. Use pressure simultaneously at the top and bottom of the 
NIM to ensure a proper fit to the midplane.

4. Secure the screws on the top and bottom of the module, being careful not to 

over-tighten.

5. For redundant NIMs, repeat this process to install the Protection NIM in slot A.