This is a thermal printer like you would find on a cash register or adding machine. It will print simple strings passed to it via TTL serial, bitmap images (poorly) and it can generate several different formats of barcodes.
The 2N5400 and 2N5401 are silicon PNP transistors designed for high voltage amplifier applications. Bipolar (BJT) Transistor PNP 150V 600mA 300MHz 350mW Surface Mount SOT-23.
The 2N6107, 2N-6107, 6107 is a 70V 7A PNP Silicone Power Transistor, designed for use in general purpose amplifiers and switching applications TO-220A/B Package.
These epitaxial planar transistors are mounted in the TO-126 plastic package. The NPN types are the BD135 and BD139, and the complementary PNP types are the BD136 and BD140.