Intermec EasyCoder 3400e, User Manual

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Communications Reference
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Communication Protocols
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
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 Character Pin 11/20
Buffer already full GS Busy
Ribbon fault US Busy
No label stock EM Busy
Buffer now full DC3 Busy
Printhead hot SI Busy
Offline (paused) DC3 Busy
Label at strip pin FS Ready
Skipping DC1 Ready
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>.