When the loopback jack is added to a span that does not contain a Smart Jack, the span is divided into two sections. See the figure and the figure. These sections are described in the table.
DS1 span section descriptions (without a Smart Jack)
Span section
Smart Jack location
Span Section 1:
ICSU to the loopback jack
Span Section 2:
Loopback jack to the CO)
Span Section 2 includes the short cable from the loopback jack to the dumb block demarcation point (part of the loopback jack). This is the only portion of section 2 that is part of customer premises wiring but is not covered in the loopback jack’s loopback path.
A problem can exist in one or both the sections. The field technician is responsible for finding and correcting problems in Span Section 1 and the loopback cable portion of Span Section 2. The DS1 service provider is responsible for finding and correcting problems in the majority of Span Section 2.
