PN 9001024
Rev. B Jan. 2000
Page 3-7
SATO CL608 & CL612 SERVICE MANUAL
SECTION 3 – Interface Specifications
TSOHNOITCENNOCRETNIRETNIRP
GF)dnuorGemarF(GF1
DTataDtimsnarTDT2
DR)ataDevieceR(DR3
)dneSottseuqeR(STR4
)dneSotraelC(STC5
)ydaeRteSataD(RSD6
* )ydaeRlanimreTataD(RTD02
GS)dnuorGlangiS(GS7
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) as previously
explained. When the printer is first powered on and goes on-line, an X-On is sent out. In
the Single Job Buffer mode, when the printer receives a viable job, it transmits an X-Off
and begins printing. When it is done printing, it transmits an X-On. In the Multi 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 data.
When it is placed back on line manually, it sends an X-On, indicating it is again available
for receipt of data. If an error occurs during printing (paper out, ribbon out), the printer
sends nothing in the Single Job Buffer mode since the last character transmitted was an X-
Off. When the error is cleared and the printer resumes printing, no X-On is sent until the
current job is completed and the printer is once again read to receive the next job. If it is in
the Multi Job Buffer mode, it sends an X-Off as soon as an error condition is detected.
When the error is cleared and the printer is placed back on-line, it transmits an X-On
indicating it is again ready to accept data.
Upon power up, if no error conditions are present, the printer will continually send X-On
characters at five millisecond intervals until it receives a transmission from the host.
3-4 RS232C Serial Interface (Cont.)
Cable Requirements
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