No Communication (General); No Serial Communication - Intermec EasyCoder 301 Service Manual

13.7 No Communi-
cation (general)
13.8 No Serial
Communication
Intermec EasyCoder 301 – Service Manual Ed. 3
Description:
The following actions are valid for all communication inter-
faces. Refer also to chapters 13.8 and 13.9.
Possible Causes and Suggested Remedies:
• Defective cable between printer and host.
- Check that the interface cable is correctly inserted and that it
is of correct type and configuration.
- Check that any clips or ground screws are properly engaged.
- Inspect cable for physical damage.
- Remove the cable and put it back a few times to rub off possible
oxide.
- Try using another identical cable.
• Error in host.
- Try connecting the printer to another host computer.
- Check communication in the Dump Mode.
Description:
The following actions are valid for the standard serial interface
"uart1:" fitted on the CPU board. Also see chapter 13.7.
Possible Causes and Suggested Remedies:
• Communication setup mismatch.
- In the Test Mode, check that the printer and host are set for the
same communication parameters, such as baudrate, parity,
character length, stopbits, new line and handshaking. Some
kind of handshaking. e.g. XON/XOFF or RTS/CTS is strongly
recommended.
• Damaged RS 232 driver circuit.
- With the aid of an oscilloscope, or some kind of line analyser
("break-out box"), verify that the interface signals to and from
the CPU board are correct. The RS 232 driver (U17) could
have been damaged as a result of voltage transients from the
interface.
• No supply voltage.
- Verify that the supply voltages +5V are present (see chapter
11.9.
• No external +5V (Pin 1 on printers serial port).
- Some external devices require current supply from the printer
(+5V). Typically, this applies to a bar code scanner. The
printer supplies max. 150 mA and is automatically turned off
at higher loads. Check the consumption of the connected
device.
• Too long cables.
- RS 232C max. length 10–15 metres (33–49 ft).
• Input buffer on host overflow.
- The input buffer should normally be handled by the software
of the host. Restart the host to empty its input buffer and try
again.
Chapter 13 Troubleshooting
72