Casio UP-250, Technical Manual

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RS-485 Serial Interface (option)
Refer to the Appendix for details.
IEEE 1284 Parallel Interface
Complies with the standard described in the IEEE 1284 specification by the Institute of Electrical
and Electronic Engineers, Inc.
Specification
Data transmission: 8-bit parallel
Synchronization: Externally supplied STROBE signals
Handshaking: and BUSY signals
Signal levels: TTL-compatible
Connector: 57RE-40360-830B (DDK) or equivalent (IEEE 1284 Type B)
Reverse communication
(Printer to host):
Nibble or byte mode
Reverse Mode (Data Transmission from Printer to Host)
Status data transmission from the printer to the host occurs in nibble or byte mode. These modes
allow data transmission from the asynchronous printer under control of the host. Data
transmissions in nibble mode are made via the existing control lines in units of four bits (a
nibble). In byte mode, data transmissions proceed by making the eight-bit data lines
bidirectional. Both modes fail to proceed concurrently in compatibility mode, causing half
duplex transmission. The IEEE 1284 nibble/byte modes are under development in draft form
and may be subject to change.
ACK
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