The polarity type determines which fibers connect from each end. With 12 fiber positions, these are the three types:
Type-A, also referred to as straight through, connects fiber 1 in the first cassette to fiber 1 in the second cassette, following this pattern through each of the 12 fiber positions—see table 1.0 below. One end is key up and the other end is in the key down position.
Table 1.0 |
Cassette 1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
|
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
Cassette 2 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
Type-B, also referred to as cross or flipped, connects fiber 1 in the first cassette to fiber 12 in the second cassette, following this pattern through each of the 12 fiber positions, with the last being 12-1—see table 1.1 below. Both ends are in the key up position.
Table 1.1 |
Cassette 1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
|
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
Cassette 2 |
12 |
11 |
10 |
9 |
8 |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
Type-C, also referred to as cross pair or rollover, connects fiber numbers in pairs, starting with 1-2 and 2-1 on one end, 11-12 and 12-11 on the other end—see table 1.2 below for all of the fiber pairings. One end is key up and the other end is in the key down position.
Table 1.2 |
Cassette 1 |
1 |
2 |
3 |
4 |
5 |
6 |
7 |
8 |
9 |
10 |
11 |
12 |
|
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
| |
Cassette 2 |
2 |
1 |
4 |
3 |
6 |
5 |
8 |
7 |
10 |
9 |
12 |
11 |