Lithium Cell

TM 11-7025-233-23

All electrically-operated teleprinter components connect to the logic board (fig.

2-1).

Figure 2-1.

Logic Board Connections

2-4. Lithium Cell. The logic board includes a lithium cell (fig. 2-1) to supply

power to memory chips storing operator-programmed functions whenever line power is

off . Loss of charge, failure of the cell, or removal of the jumper next to the

cell causes loss of these memory functions. Without them, the teleprinter has no

references and will not operate until the cell is operational and the memory

reprogrammed.

2-5. EXTENDED BUFFER

The teleprinter prints at 120 cps. Usually, data is received at a much higher

rate. So that the teleprinter isn't constantly sending a busy signal to tell the

computer to wait until it catches up, a buffer on the logic board stores 640

characters for the printing mechanism to work on while the computer tends to other

business. As the transmission baud rate increases, the 640-character buffer

becomes inadequate. The extended buffer adds storage for an additional 2000

characters, making high speed transmission practical and improving efficiency at

lower rates. The extended buffer mounts on and connects to the logic board.

2-2