User`s manual

CBM-202PC User’s Manual
23
CITIZEN
Signal Names and Functions
SIGNAL NAME PIN NO. I/O FUNCTION
TXD 13 Output
Transmits status.
When data receiving is not available while in
XON/XOFF, XOFF (13H) is transmitted.
When receiving is made possible, XON (11H) is
transmitted.
RXD 15 Input
Receiving data signal.
On occurrence of a framing error or parity error, the
data are printed in "?".
DSR 100 Input
With this signal held in "LOW" when data are
transmitted from CPU while DTR/DSR has been
selected, transmitting takes place. With this signal
held in "HIGH", transmitting is does not take place
until it gets "LOW".
DTR 12 Output
Transmits data while this signal is held in "LOW".
If writing takes place while in "HIGH", overrun error
is created, where data are ignored.