No Serial Communication - Intermec EasyCoder 601 XP Service Manual

17.9 No Serial
Communication
Intermec EasyCoder 601 XP – Service Manual Ed. 3
Description:
The following actions are valid for the standard serial interface
"uart1:" fitted on the CPU board and to some extent also to any
other serial interfaces on optional interface boards. Also see
chapter 17.8.
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 (IC304) could
have been damaged as a result of voltage transients from the
interface. Being socket-mounted, this circuit is easy to replace.
Repeated damage is, however, an indication of insufficient
cable screening, or the electrical environment being too noisy.
• No supply voltage.
- Verify that the supply voltages +5V are present (see chapter
15.5.
• No external +5V.
- Some external devices require current supply from the printer
(+5V). Typically, this applies to the Intermec External Keyboard
or a bar code scanner. The printer supplies max. 200 mA and
is automatically turned off at higher loads. Check the
consumption of the connected device.
- The polyswitch (RP30 on the CPU board; RP1 on the Industrial
Interface Board and RP1 and RP2 on the Double Serial
Interface Board) may be out of range and need to be replaced.
• Too long cables.
- RS 232C
- RS 422 & RS 485 Max. length 1,200 metres (4,000 ft)
- Current Loop
• Input buffer on host overflow.
- The input buffer should normally be handled by the software
of the host. Increase the receive buffer in the printer to a large
value, restart the host to empty its input buffer and try again.
• No response from printer when running a custom-made pro-
gram.
- The verbosity can be controlled by means of the Fingerprint
instructions VERBON/VERBOFF and SYSVAR(18). In the
Intermec Direct Protocol, verbosity is by default disabled.
Check the program for instructions that may affect the ver-
bosity.
- Verify that the correct communication port is selected as
standard IN/OUT channel.
Chapter 17 Troubleshooting
Max. length 10–15 metres (33–49 ft)
Max. length 500 metres (1,500 ft)
149