User`s manual

119
Barcode Handy Terminal
5.5 Basic Communication Specifications and
Ymodem Communication
5.5.1 Basic Communication Specifications
The table below lists communication specifications when the BHT exchanges data with the host computer
using the IrDA interface or connector interface.
IrDA Interface Connector Interface
Synchronization Start-stop
Transmission speed
9600, 19200, 38400,
57600, 115200 bps
300, 600, 1200, 2400,
4800, 9600, 19200,
38400, 57600, 115200 bps
Transmission code ASCII 8-bit code ASCII 7-bit or 8-bit code
Transmission bit order LSB (Least significant bit) first
Vertical parity None Even, odd, or none
 Synchronization
For accurate data transaction, it is necessary to synchronize transmission between the sender and
receiver. To achieve this, the bit order and position, character length, and beginning and end of the
character to be transmitted must be defined beforehand.
Start-stop synchronization is an asynchronous system that synchronizes each character as a unit; that is,
it externally adds start and stop bits to the leading and trailing bit positions of the character to be
transmitted, respectively. Data sampling is commenced upon receiving the start bit, and when the stop bit
is received, sampling is completed and communication ceased. The number of stop bits can be selected
(1 or 2 bits).
 Transmission Speed
This is the maximum number of bits that can be transmitted per second, and is expressed in bps (bits per
second).
 IrDA Interface Communication Range
The maximum effective range of the IrDA interface is 15 cm, with the IR beam within a 10° angle of
divergence.
 IrDA Interface Transmission/Receipt Switching Time
The IrDA interface must satisfy the following conditions for transmission and receipt switching.
(1) The IrDA interface must be ready to receive within 10 ms following the completion of transmission.
(2) The IrDA interface must commence transmission after waiting at least 10 ms following the completion
of receipt.