Troubleshooting - Acksys MI400 Series Technical Documentation Manual

In idle state (no line activity), the TX and RX lamps should be off, and the POWER lamp
should be on. The status of the other lamps depends on the operating mode.
− Check that the RX lamp is off in the idle state (no line activity).
If this is not the case, the problem is probably due to incorrect installation (inverted bias)
or because the line is not biased. Only one bias per line is required.
−
The TX lamp remains off
Check the following:
In RS232 transmission, if the serial driver needs control signals, configure SW2. In most
cases, permanently enabling CTS, DSR and DCD is sufficient.
The RS232 connection cable (with PCs, the cable should not be crossed, and SW1 should be
set to DTE position). The RS232 cables supplied with the unit are not crossed.
The position of switch SW1:
with an uncrossed cable and a PC: DTE position
with a crossed cable and a PC: DCE position
with an uncrossed cable and a MODEM: DCE position
with a crossed cable and a MODEM: DTE position
− In RS422 point-to-point or multipoint master mode, the RTS/DTR lamp
remains off.
Configure SW2 in permanent transmission validation mode.
− In RS422 multipoint slave mode or in RS485 mode the RTS/DTR lamp is
always on.
Check the configuration of SW2:
In these two modes, transmission cannot be validated permanently, but it must be
controlled by either the RTS signal or by the DTR signal, depending on the serial
driver.
Check that the serial driver correctly handles the RTS or DTR signal (see the signal-timing
diagram on page 2-5). If not, generate the RTS signal with a shunt (configuration n°1
or n°2 on pages 2-7 and 2-8), or use the xxMI400/RTS model with automatic
transmission control.

TROUBLESHOOTING

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