TallyGenicom 3860 User Manual

Also see for 3860: Product guide Specifications Specifications Quick reference guide

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TallyGenicom 3860 User Manual Manual pdf 100 page image

3860/80 User’s Manual12-2ParametersIn order for devices to communicate via RS-232, the character frames (baud rate, number ofdata bits, parity, number of stop bits), as well as the handshaking, must be set the same at thetransmitter and receiver.The factory default settings for the character frame are 9600 baud, 1 start bit, eight data bits,one stop bit. The factory defaults for parity are: Ignore received parity and transmit evenparity.The computer expects to receive the READY/BUSY status (handshaking) and fault statusfrom the printer by receiving a special character (busy by code), or by reading the DC voltageon one or more of several signal wires (busy by level).As shipped, the printer is set to indicate READY/ BUSY by code (XON/ XOFF) and also bylevel (DTR and SRTS). A fault condition is reflected in XON/XOFF and DTR.DOS MachinesFor those using personal computers, the default handshaking is compatible, and the defaultcharacter frame matches the DOS defaults. Always set DOS serial parameters explicitly withthe MODE command in DOS.Seven or Eight Data BitsA few years ago, a typical character-imaging device (CRT terminal or printer) would renderabout 94 symbols. This reflects the limits of the teletype machine, which is a conceptualdescendent of the typewriter. It only takes seven bits of data to select among 128 symbols orcontrol codes.When seven-bit data is used, the eighth bit in the byte is often used as a parity bit. The paritybit might be set so that the number of ones in the byte is always even (even parity) or alwaysodd (odd parity). This serves as an error check. The parity bit can also be set to always bezero (space) or always be one (mark).As character-imaging devices have come to support more symbols, such as line-drawingsymbols, and characters from non-English alphabets, a common method for transmitting theseadditional characters is to use the eighth bit for data.