Specifications

32 DR300
3. Interface Specification Operation Manual
Ready/Busy Flow Control
Ready/Busy is the hardware flow control for the serial interface on
the printer. By raising/lowering the voltage level on Pin 20 of the
RS232 port, the printer notifies the host when it is ready to receive
data. Pin 4 (RTS) and Pin 20 (DTR) are the important signals on
the printer for this method of flow control. The host must be capable
of supporting this flow control method for it to function properly.
Cable Requirements
* This connection at the host side of the interface would depend
upon the pin that is being used as the Ready/Busy signal by the
driving software. Typically on a PC, it would be either CTS (pin 5)
or DSR (pin 6) on a DB-25 connector.
X-On/X-Off Flow Control
X-On/X-Off flow control must be used whenever hardware (Ready/
Busy) flow control is not available or desirable. Instead of a voltage
going high/low at pin 20, control characters representing “Printer
Ready” (X-On = 11 hexadecimal) or “Printer Busy” (X-Off = 13
hexadecimal) are transmitted by the printer on pin 2 (Transmit
Data) to the host. In order for this method of flow control to function
correctly, the host must be capable of supporting it. X-On/X-Off
operates in a manner similar to the function of pin 20 (DTR)aspre-
viously explained. When the printer is first switched on and goes
on-line, an X-On is sent out. In the Single Job Buffer mode, when
the printer receives a print job, it transmits an X-Off and begins
printing. When it is done printing, it transmits an X-On.IntheMulti
Job Buffer mode, the printer sends an X-Off when the “Buffer Near
Full” level is reached and a X-On when the data level of the buffer
drops below the “Buffer Available” mark. When the printer is taken
off-line manually, it transmits an X-Off indicating it cannot accept
HOST INTERCONNECTION PRINTER
FG 1 FG (Frame Ground)
TD 3 RD (Receive Data)
4 RTS (Request to Send)
5CTS(CleartoSend)
6 DSR (Data Set Ready)
* 20 DTR (Data Terminal Ready)
SG 7 SG (Signal Ground)