User Manual

93
Serial Port Interface
6/4/08 GX420d User Guide 980611-001 Rev. B
Serial Port Interface
The maximum current available through the serial and/or parallel port is not to
exceed a total of 0.75 Amps.
When XON/XOFF handshaking is selected, data flow is controlled by the ASCII
control codes DC1 (XON) and DC3 (XOFF). The DTR control lead will have no
effect.
Interconnecting to DTE Devices — The printer is configured as data terminal
equipment (DTE). To connect the printer to other DTE devices (such as the serial
port of a personal computer), use an RS-232 null modem (crossover) cable. Figure
31 shows the required cable connections.
Interconnecting to DCE Devices — When the printer is connected via its RS-232
interface to data communication equipment (DCE) such as a modem, a STAN-
DARD RS-232 (straight-through) interface cable must be used. Figure 32 shows
the connections required for this cable.
Connecting to the KDU (Keyboard Display Unit) — The KDU was designed for
DCE printer connections and requires a Zebra custom serial port gender changing
adapter. The KDU now includes the KDU adapter and the Zebra kit part number
for the KDU Adapter is 105934-088.
Pin Description
1 Not used
2 RXD (receive data) input to the printer
3 TXD (transmit data) output from the printer
4 DTR (data terminal ready) output from the printer -- controls
when the host may send data
5 Chassis ground
6 DSR (data set ready) input to the printer
7 RTS (request to send) output from the printer -- always in the
ACTIVE condition when the printer is turned on
8 CTS (clear to send) - Not used by the printer
9 +5 V @ 0.75 A fused