Communication Protocols; Intermec Standard Protocol - Intermec EasyCoder 3400e User Manual

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Communication protocols are important because they determine the transmission
standards for communication between the printer and the host. The printer and the host
must use the same protocol and parameters to communicate properly. The printer
supports the flow control and block transfer protocols described in the next sections.
All of these protocols are point-to-point except Multi-Drop. Application programs
and/or ROM BIOS determine which protocols your computer can support. For more
detailed information, refer to the Intermec Data Communications Reference Manual
(Part No. 044737).
Intermec Standard protocol is a proprietary block transfer/status response protocol. For
each block sent, the host must wait for the appropriate response before sending the next
block (<DC1>). Except for single character status commands (<ENQ> and <VT>),
Standard protocol transmits characters in message blocks beginning with the start of
text (<STX>) character and ending with the end of text (<ETX>) character. Message
blocks can be up to 255 characters, including the start of text and end of text characters.
The printer auto-discriminates between Standard, Polling Mode D, and Multi-Drop
protocols.
The printer returns its highest priority status when it receives a valid block (<STX>
data <ETX>) or when it receives the status request command <ENQ>. When the printer
receives the status dump command (<VT>), the printer returns all active status. The
printer status response time ranges from 30ms to 100ms depending on the complexity
of the received message block. In the case of a transmission error, the printer responds
with a <NAK> and discards the entire message block.
The table below shows printer status conditions in descending order of priority, status
response characters, and pin 11/20 states:
Printer Status
Buffer already full
Ribbon fault
No label stock
Buffer now full
Printhead hot
Offline (paused)
Label at strip pin
Skipping
Printing
Ready/Online
Note: Do not confuse the Buffer now full <DC3> status with the XON/XOFF
characters <DC1> and <DC3>.
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Communications Reference
Character Pin 11/20
GS Busy
US Busy
EM Busy
DC3 Busy
SI Busy
DC3 Busy
FS Ready
DC1 Ready
DC1 Ready
DC1 Ready
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