Assessments - 3, GPA: 4.3
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(Active “Low”) • Busy: A signal to indicate a busy state of the printer. Input new data when this signal is “Low”. (Active “High”) • nFault: This signal becomes “Low” when alarmed. At this time, all control circuits in the printer are deactivated. (Active “Low”) • PError: A signal to indicate that the paper supply has become low or has run out completely. (Active “High”) • DK_STATUS: This signal becomes “High” when the switch is open, and “Low” when it is closed. Power related signal • +5 V: A 5 V signal, which is pulled up by a 3.3 KW resistor. • GND: Common ground on circuits. — 27 — 6.2.2 Electrical Characteristics Input signal level (STB, DATA 1-8) All the input signals are at the C-MOS level. “HIGH” level: 4.0 V minimum “LOW” level: 0.9 V maximum Output signal level All the output signals are at the C-MOS level. “HIGH” level: 2.4 V minimum “LOW” level: 0.4 V maximum Input and output conditions All the input signals, DATA 1-8, are each pulled up with 50 kW resistor, and the other input signals are each pulled up with a 3.3 kW resistor. [Printer Side] [Host Side] Vcc Twisted Pair Wire All the output signals, DATA 1-8, are each pulled up with a 50 kW resistor, and the other output signals are each pulled up with a 3.3 kW resistor. [Printer Side] [Host Side] Vcc Twisted Pair Wire — 28 — 6.2.3 Timing Chart (Compatibility Mode) Data input and print timing T6 T1 T3 T2 T4 T5 Power DATA nStrobe BUSY nAck T1, T2, T3: 0.5 .s MIN T4: 270 ns MAX T5: 2.3 .s TYP T6: 500 ms MIN (At power- on) 6.2.4 Data Reception Control When the Busy signal is at “LOW”, the printer can receive data from the host computer, but when at “HIGH”, data reception is not possible. 6.2.5 Buffering Since the printer can buffer 4K bytes of data, the host computer is immediately made free. — 29 — 7. SERIAL INTERFACE 7.1 Specifications (1) Synchronizing system Asynchronous (2) Baud rate 2400, 4800, 9600, or 19200 bps (User selectable) (3) Configuration of one word Start bit: 1-bit Data bits: 7 or 8-bits (User selectable) Parity bit: Odd, even, or none (User selectable) Stop bit: 1-bit or more (4) Signal polarity RS-232C • Mark = Logic “1” (–3 V to –12 V) • Space = Logic “0” (+3 V to +12 V) (5) Received data (RD signal) RS-232C • Mark = 1 • Space = 0 (6) Reception control (DTR signal) RS-232C • Mark: Data transfer disabled • Space: Data transfer enabled (7) Transmission control (TD signal) DC1 code (11H)X-ON: Data reception enabled DC3 code (13H)X-OFF: Data reception disabled — 30 — 7.2 Connector Pin Configuration 7.2 Connector Pin Configuration No. Signal name Input/output Function 1 FG — Grounding for safety 2 TD Output Transferred data 3 RD Input Received data 4 RTS Output Same as DTR 6 DSR Input Data set ready or reset (Selected with a DIP switch) 7 GND — Ground for signals 20 DTR Output Printer Busy signal 25 INIT Input Reset (Selected with a DIP switch) Applicable connectors (D-Sub connectors) Printer side: 17LE-13250 (DDK) or equivalent Cable side: 17JE-23250 (DDK) or equivalent CAUTION: • Signals for RS-232C are specified based on EIA RS-232C. • While data is not being transferred, always maintain the received data in a mark state. — 31 — 7.3 Description of Input and Output Signals 7.3 Description of Input and Output Signals 7.3.1 Input and Output Signals (1) RD This is a serial reception data signal. When a framing error, overrun error or parity error occurs, the data containing the error is printed as a “?”. (2) DTR, RTS When this signal is Ready, you can write data or commands into the input buffer. If you do so while the signal is Busy, an overrun error occurs, and the previously written data will be ignored. Data can be written into the input buffer even during printing. A Busy signal is also issued at the time of power-on, test printing, online communication, and resetting. (3) TD As data is received, the remaining capacity of the printer’s input buffer decreases. When it becomes less than 128(10) bytes, a DC3 (13H) (Data reception disable signal) is output to the host computer. On the other hand, when the remaining capacity of the input buffer increases to 256(20) or more bytes, a DC1 (11H)(Data reception enable signal) is output to the host computer. Note: The values in ( ) are for when the 72 bytes of the input buffer is selected by DIP switches. (4) DSR During status information transmission, if DTR/DSR control is selected, the host computer transfers data to the printer after checking this signal is a space. If DTR/ DSR control is not selected, the host computer ignores this signal and sends data to the printer. Also, this signal can be used as a reset signal after switching a DIP switch. (See “5.2 Table for Setting DIP Switches”.) When the pulse width of the signal is 1 ms or longer, a reset will be applied. (5) INIT This signal can be used as a reset signal after switching a DIP switch. (See “5.2 Table for Setting DIP Switches”.) When the pulse width of the signal is 1 ms or longer in space state, a reset will be applied. (6) ...