BiDi_WDM

# 波長對應命名法
3	1310 nm
4	1490 nm
5	1550 nm

Situation

# 使用單芯GBIC(波長1550nm, 1310nm)但是沒有link
No link using single-strand GBIC (1550nm/1310nm).

Solution

# U4要接D4
U4：TX 1310 nm / RX 1490 nm
D4：TX 1490 nm / RX 1310 nm

# U5要接D5
U5：TX 1310 nm / RX 1550 nm
D5：TX 1550 nm / RX 1310 nm

# 剛好U4跟U5的GBIC上面印刷的字表示TX = 1310，要仔細看裡面的U4 U5
Both U4 and U5 GBICs are labeled with TX = 1310nm. Look closely at the U4/U5 model names to differentiate them.