Genicom EasyCoder 3400e - Manual (Page 99)

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Helvetica CondensedHelvetica Appendix C— Communications Reference
EasyCoder 3400e Bar Code Label Printer User’s Manual 87
Intermec Standard Protocol Printer Status Conditions (continued)
Printer Status Character Pin 11/20
Printing DC1 Ready
Ready/Online DC1 Ready
Note: Do not confuse the Buffer now full <DC3> status with the
XON/XOFF characters <DC1> and <DC3>.
When the printer returns Buffer Now Full (<DC3>) status, it accepts the
currently received message block. At this time, the printer can accept short
messages to allow parsing of immediate commands such as Reset (<DLE>)
or Cancel Batch Printing (<EM>). However, if the printer responds with a
<GS> to any message block, the buffer is already full and the printer
discards the entire message block.
XON/XOFF Protocol (Software and Hardware Flow Control)
The XON/XOFF protocol stops the host from sending data when the
printer buffer fills up and starts the host again when the buffer empties.
When you select this protocol, you concurrently enable software and
hardware flow control. Software flow control uses the ASCII characters
<DC1> (XON) and <DC3> (XOFF) to start and stop the flow of data
from the host to the printer. Hardware flow control uses pin 11 or pin 20
(internally connected together) on the printer’s serial port to indicate
“Ready” or “Busy” for data flow control. As with Standard protocol,
<STX> and <ETX> enclose data. Status responses conform to the table
above except that <DC2> is substituted for <DC1> and <DC4> is
substituted for <DC3>.
The printer does not restrict the message length for XON/XOFF protocol.
That is, the printer processes information as it is being downloaded and
stops when there is no more information. There is no restriction on the
number of characters that can be sent down at a time. <STX> and <ETX>
are optional characters.
Pin 11/20 reports “Ready” and a <DC1> (XON) is transmitted when the
printer finishes reloading at power-up. Pin 11/20 reports “Busy” when the
printer’s input buffer fills with 768 bytes of data. If the host ignores pin
11/20 and continues to transmit data, the printer transmits a <DC3>
(XOFF) after receiving 15 additional characters. The printer continues to
transmit a <DC3> after every 15 characters received if the host continues
to transmit data. Data integrity is not guaranteed if this happens.
Pin 11/20 becomes “Ready” when the printer has transferred all the data
from the input buffer. If the printer receives a <DC3>, it transmits a
<DC1> (XON) and the host may resume transmission. When you switch
the printer offline, pin 11/20 becomes “Busy” and it transmits a <DC3>.