Samsung SRP-350PG - SRP 350 B/W Direct Thermal Printer Service Manual page 62

7 Special Circuit Description
7-9 Thermal Printer Circuit
256 CLK
CLK
DATA#1,2
256 Bits 256 Bits 256 Bits
LATCH
Printing(1~256) Printing(1~256)
STB1
Printing(257~512)
STB2
Data#1 and Data#2 Pins are shorted on Main PCB. So, the Data(256 Bits) are stored in both Shift Register #1 and #2.
Table 7-15 Thermal Printer Timing Waveform
Samsung Electro-Mechanics 7-11