Intermec EasyCoder 3400e, Руководство пользователя

Страница: 119 / 150

HelvC
NugFont
C 39
Communications Reference
C-5
C
This table shows the printer XON/XOFF operation:
# of Bytes Received Online/Offline Pin 11/20 Transmit
Do not care Offline Busy DC3
768 Online Busy
768 + each 15 thereafter Online Busy DC3
Buffer Empty Online Ready DC1 (if DC3 was sent)
XON/XOFF, No Status Protocol
This protocol is identical to XON/XOFF protocol except that status is not returned after
each message received. However, status is still returned for the status request (<ENQ>)
and the status dump (<VT>) commands.
Polling Mode D
Polling Mode D is a block transfer protocol that transmits data in blocks of up to 255
characters, including protocol overhead. For Polling Mode D, the host/concentrator is
responsible for asking the printer for data it might have (polling) and requesting to send
data to the printer (selecting). The blocks are framed with LRC characters for additional
data integrity. Polling Mode D is normally used for point-to-point networks that
connect the printer to an Intermec port concentrator (RS-232 or RS-422 are acceptable).
This protocol is the default setting for the printer. Return the protocol setting to Polling
Mode D by setting the printer DIP switches to the factory default settings (9600, E, 7, 1).
Multi-Drop Protocol
Use Multi-Drop protocol to connect up to 32 devices to an Intermec controller on a
four-wire RS-485 (two twisted pair). This protocol is similar to Polling Mode D except
each device has a unique address (POL and SEL character). You must use an RS-485,
which is automatically enabled when you enable Multi-Drop. Be sure to specify a
unique address for the printer and verify that the baud rate is between 2,400 and 19,200.
User-Defined Protocol
The printer provides the capability to change protocol characters. However, the user
may not define their own protocol. You can substitute characters you want to use as
protocol characters, but the rules for the chosen protocol do not change. The printer
does not use any protocol characters that you replace with the NUL character. One table
of protocol characters exists. You may redefine these characters to create a table that all
of the protocols can use. One possibility for the user to redefine protocol characters
might be the replacement of control characters with printable characters.