- Hewlett-Packard Printer Owner's Manual

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IMPORTANT:
Before you proceed with cabling, you must know
whether the devices that you will connect to Print Master are DTE
(Data Terminal Equipment) or DCE (Data Communication
Equipment). The following devices are generally DTE: terminals,
printers, and computers like the IBM PC. The following devices are
DCE: modems and some computers.
If your device transmits data on Pin 2 and receives data on Pin 3, it is
DTE. If your device receives data on Pin 2 and transmits data on Pin
3, it is DCE. However, to verify the interface requirements, please
refer to the Owner's Manual for your device.
Serial ports on Print Master have DB-25 female DCE connectors.
DCE ports use the following signals for communication:
DCE PORT PIN/SIGNAL DEFINITION
Pin Signal
(EIA-232)
Direction Description
1 PGND --- Protective Ground
2 Tx Input Data In
3 Rx Output Data Out
4 RTS Input Request To Send (Not Used)
5 CTS Output Clear To Send: - Voltage When Print Buffer Full
6 DSR Output Data Set Ready: + Voltage When Print Master Powers Up
7 SGND --- Signal Ground
8 DCD Output Data Carrier Detect: + Voltage When Print Master Powers Up
20 DTR Input Print Master Transmit Enabled When +12 Volts. Internally
Enabled If No Wire Connected.