Rs-232C Serial Interface; Hardware Requirements; Figure 5.5 Rs-232C Interface Input Circuit; Figure 5.6 Rs-232C Interface Output Circuit - Fujitsu PrintPartner 12V Product Description

5.3 RS-232C Serial Interface

53.1 Hardware requirements

Signal levels:
-3 V or lower for a mark condition (logical 1)
+3 V or higher for a space condition (logical 0)
Input circuit:
An MC1489AL or equivalent is used to convert from the RS-232C level to the TI' L level.
Figure 5.5 shows the RS-232C interface input circuit.
Output circuit:
An MC1488L or equivalent is used to convert from the TI' L level to the RS-232C level.
A l000-pF capacitor suppresses noise on the output signal line.
Figure 5.6 shows the RS-232C interface output circuit

Figure 5.5 RS-232C interface input circuit

Figure 5.6 RS-232C interface output circuit

T
1000 pF
5-7