Citizen Systems iDP-3550 - Manual (Page 47)

10.3.3 Error Detection
A parity error, framing error, and overrun error are detected. When an error is detected, that data is stored
in the buffer as "?".
(1) Framing error
This error results when a space is detected in detecting the stop bit. That data is stored in the buffer
as "?".
(2) Parity error
If a parity check has been specified and an error is detected at the time of parity check, that data is
stored in the buffer as "?".
(3) Overrun error
If an overrun error is detected, that data is stored in the buffer as "?".
10.3.4 Data Receiving Control
When the DTR signal is a space, the data from the host side can be received. When it is a mark, however,
the data cannot be received.
10.3.5 Buffering
The DTR and TXD signals are available as control signals to transfer the data to the input buffer.
10.3.6 Electrical Characteristics
(1) RS-232C circuit
Input (RXD, DSR, mRXD)
[Printer Side] [Host Side]
Output (DTR, TXD, mTXD, RCH, RTS, FAULT)
Equivalent to MAX232
RXD
Mark=(-8V): Stop bit
Space=(+8V): Start bit