User`s manual

BD2-1220/1221 User’s Manual
20
7.6 Data Reception Control
When the DTR/DSR control mode is selected, host data can be received if the DTR signal is at Space, while
it is not receivable if the signal is at Mark. When the DTR/DSR control mode is deselected, host data can be
received after XON is transmitted, while it is not receivable after XOFF is transmitted.
7.7 Buffering
Data transfers to the input buffer are controlled by the DTR and TD signals. The input buffer has a 4K-byte
capacity, so the host is freed immediately after data transfer completes.
(1) DTR signal (Refer to 7.2 (2))
(2) TD signal (Refer to 7.2 (3))
7.8 Connections to Serial Port
(1) Connections to the 25-pin/9-pin serial port
Note: The diagram above is a typical connection to the host. When inline cable connection is required, the
DTR/DSR and RD/TD lines must be reversed each.
(2) Connections to other parallel port
When connecting to other parallel port, carefully check the signal names and their destinations, and establish
correct connections.
20
DTR
TD
RD
DSR
GND
DSR
RD
TD
DTR
GND
21
22
23
3 (4)
6
3
2
20
7
CN1
25-pin serial interface
20
DTR
TD
RD
DSR
GND
DSR
RD
TD
DTR
GND
21
22
23
3 (4)
6
2
3
4
5
CN1
9-pin serial interface