Motorola DS3478 - Manual (Page 109)

RS-232 Interface 7 - 11
Data Bits
This parameter allows the digital scanner to interface with devices requiring a 7-bit or 8-bit ASCII protocol.
Hardware Handshaking
The data interface consists of an RS-232 port designed to operate either with or without the hardware handshaking
lines Request to Send (RTS) and Clear to Send (CTS).
Disable Standard RTS/CTS handshaking to transmit scan data as it becomes available. Enable Standard RTS/CTS
handshaking to transmit scan data according to the following sequence:
• The digital scanner reads the CTS line for activity. If CTS is asserted, the digital scanner waits up to the Host
Serial Response Time-out for the host to de-assert the CTS line. If the CTS line is still asserted after the Host
Serial Response Time-out expires (default), the digital scanner sounds a transmit error and discards any
scanned data.
• When the CTS line is de-asserted, the digital scanner asserts the RTS line and waits up to the Host Serial
Response Time-out for the host to assert CTS. When the host asserts CTS, the digital scanner transmits
data. If the CTS line is still de-asserted after Host Serial Response Time-out expires (default), the digital
scanner sounds a transmission error and discards the data.
• When data transmission completes, the digital scanner de-asserts RTS 10 msec after sending the last
character.
• The host responds by de-asserting CTS. The digital scanner checks for a de-asserted CTS upon the next
data transmission.
During data transmission, the CTS line should be asserted. If CTS is de-asserted for more than 50 ms between
characters, the digital scanner aborts transmission, sounds a transmission error, and discards the data.
If this communications sequence fails, the digital scanner issues an error indication and discards the data. Rescan
the data.
If hardware handshaking and software handshaking are both enabled, hardware handshaking takes precedence.
7-Bit
*
8-Bit
NOTE The DTR signal is jumpered (set) to the active state.