Motorola DS3478 User Manual

RS-232 Interface 7 - 11

This parameter allows the digital scanner to interface with devices requiring a 7-bit or 8-bit ASCII protocol.

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.

The DTR signal is jumpered (set) to the active state.