Compaq P5000 Series setup guide RS-232 and RS-422 Serial Interfaces, Input Signals, Output Signals

Chapter 5 RS-232 and RS-422 Serial Interfaces

RS-232 and RS-422 Serial Interfaces

NOTE: The RS-232 and RS-422 serial interface circuit characteristics are compatible with the Electronic Industry Association Specifications EIA®-232-E and EIA-422-B.

The RS-232 and RS-422 serial interfaces enable the printer to operate with bit serial devices that are compatible with an RS-232 controller. The input serial data transfer rate (in baud) is selectable from the printer control panel. Baud rates of 600, 1200, 2400, 4800, 9600, 19200, 38400, 57600, and 115K are available. The default is 9600.

NOTE: If you select a baud rate that is 19200 or greater, you may need to increase the Buffer Size in K parameter from the default (8 Kbyte), to improve performance.

The input format consists of a single start bit, 7 or 8 data bits, and one or two stop bits. The number of data bits is determined by printer configuration. The data bits are interpreted with the least significant bit first. Parity checking is determined by printer configuration options selected from the control panel.

The printer interface uses a first-in/first-out buffer. The asynchronous interface accepts data as it is provided by the host. The length of the data cable from the host computer to the printer must not exceed 50 feet (15 meters) for RS-232 or 4000 feet (1220 meters) for RS-422. A copper conductor, twisted-pair telephone cable with a shunt capacitance of 16 pF/ foot (52.5 pF/meter) terminated in a 100 ohm resistive load must be used for the RS-422.

Table 15. RS-232 Serial Interface Connector Pin Assignments

Input Signals		Output Signals		Miscellaneous
Signal	Pin	Signal	Pin	Signal	Pin
Receive Data (RD)	3	Transmit Data (TD)	2	Chassis Ground	1
Clear To Send (CTS)	5	Request To Send (RTS)	4	Signal Ground	7
Data Set Ready (DSR)	6	Data Terminal Ready (DTR)	20
Data Carrier Detect (DCD)	8

Table 16. RS-422 Serial Interface Connector Pin Assignments

Input Signals		Output Signals		Miscellaneous
Signal	Pin	Signal	Pin	Signal	Pin
- Receive Data (-RD)	15	- Transmit Data (-TD)	19	Chassis Ground	1
+ Receive Data (+RD)	17	+ Transmit Data (+TD)	25	Signal Ground	7

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