window 1. An opening or opportunity for passage of data frames or packets without the requirement for an acknowledgement from the receiving device. See modulo and TCP. 2. An opening or opportunity for passage of a range of wavelengths in a fiber optic transmission system (FOTS). For example, a laser diode might fire at 1550 nm, referring to a range of wavelengths with a nominal center point of 1550 nm. A light-emitting diode (LED) might fire at 850 nm, and a vertical cavity surface-emitting laser (VCSEL) at 1300 nm or 1310 nm. The ITU-T has established a number of standard windows, as detailed in Table 74570c23.qxd 9/11/07 12:37 PM Page 541 |