IBM EasyCoder 3400e user manual XON/XOFF, No Status Protocol, Polling Mode D, Multi-Drop Protocol

Communications Reference 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.

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