(14)Input/Output Signals
Printer
TD
RD
RTS
CTS
DSR
SG
DTR
Host
(15) Connector Pin Assignment and Signal Description
Pin No. | Signal | Function | Signal Direction |
| Name |
|
|
|
|
|
|
1 | (N.C) |
|
|
2 | TD | z Line for data which the printer sends to the host | Printer → |
|
| z Logic 1 is a Low level, while logic 0 is a High level. |
|
|
| z It is in the Low (Mark) state when no transmission is in |
|
|
| progress. |
|
3 | RD | z Line for data which the printer receives from the host | ← Host |
|
| z Logic 1 is a Low level, while logic 0 is a High level. |
|
|
| z It is in the Low (Mark) state when no transmission is in |
|
|
| progress. |
|
4 | DSR | z Input signal from the host | ← Host |
|
| z For the printer to receive data, it must be at “High” level. |
|
5 | SG | z Ground line for all data and control signals |
|
6 | DTR | z Output signal to the host | Printer → |
|
| For the READY/BUSY (DTR) protocol or XON/XOFF |
|
|
| (DC1/DC3) protocol + READY/BUSY (DTR) protocol: |
|
|
| z It indicates the ready state for the received data. |
|
|
| z It is at the “Low” level when the receive buffer is near |
|
|
| full, and at the “High” level when near empty. |
|
|
| For the XON/XOFF (DC1/DC3) protocol or RTS protocol: |
|
|
| z After the power is turned on, it is always at “High”. |
|
7 | CTS | z It is an input signal indicating whether or not the data | ← Host |
|
| transmission to the host is possible. However, this printer |
|
|
| does not detect this signal. |
|
8 | RTS | z Output signal to the host | Printer → |
|
| For the RTS protocol: |
|
|
| z It indicates the ready state for the received data. |
|
|
| z It is at “Low” when the receive buffer is nearly full, and |
|
|
| at “High” when nearly empty. |
|
|
| For protocol other than the RTS protocol: |
|
|
| z After the power is turned on, it is always at the “High” |
|
|
| level. |
|
9 | (N.C) |
|
|
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