Heralding of single photon at 1550 nm from pump pulsed non degenerate spontaneous parametric downconversion is demonstrated. P(1) and P(2) of our source are 0.1871 and 2.4 x 10 ^-3 respectively. Triggering of our source is 2.16 x 10^5 trigger.s^-1. This source may be used in QKD system.