Why am I unable to download a configuration file to a 4xxx or 5xxx Series gateway, and the Debug Port LED is on?
The ACT LED is hardware driven by the TXD signal of the PC connected to it.
There is an issue with some Dell latitude laptops where the DC power
supply causes the TXD signal to go active. During this state, ProSoft Configuration Builder,
hyperterminal, and other serial communications packages are unable
to connect or use the serial port. Disconnect the external power cable from the laptop
and check if the ACT LED goes inactive. If so, then communications should be restored.