# How do I identify the SMD component marked as !3S 4?

I have a SOT-23 SMD component marked $$\\underset{\bullet}{\vert}3\bar{\textrm{S}}\;\bar{4}\$$ as shown in the following images

I managed to find out that $$\\textrm{3S}\$$ stands for MMBT5551 NPN transistor. But I couldn't find the meaning of the prefix $$\\underset{\bullet}{\vert}\$$ and of the $$\\bar{4}\$$. I appreciate any help you can give me with it.

• BTW, +1 for the excellent markup Apr 19 '19 at 12:19

The dot of the $$\\underset{\bullet}{\vert}\$$ mark is the pin 1 marking (do check the datasheet, it has a pin numbering as well).
The combination of $$\\underset{\bullet}{\vert}\$$ means it was manufactured by a Philippine Subcontractor.