Receiving FC lights on all channels.Possible causes are::
1. The muxes are in a remote down state.
2. The muxes 8k dynamic transmit buffer has been exceeded, due to DTE failing to acknowledge the flow control request sent from the mux that has the FC LEDS on.
3. The mux has a bad db25 pin , or a bad cable / connector or the DTE has a bad interface pin.
Incorrect dipswitch settings on either the channel card or aggregate card.
Ribbon cable not secure or possible bent male pin under the ribbon connectors.