
Chapter 1 - Introduction and Description
Front Panel
The front panel has four groups of LEDs that provide the status of the four port connections, plus a LED that provides the status of Hub activity and and a LED that provides the status of System activity.
Figure 1-2.  Front Panel
Modem Ports (Ports 1, 2, 3, and 4)
Modem LEDs are Green and indicate the following:
| RD | The Receive Data indicator blinks when the modem is receiving data. | 
| TD | The Transmit Data indicator blinks when the modem is transmitting data. | 
| CD | The Carrier Detect indicator is lit when the modem detects a carrier signal. | 
| TR | The Terminal Ready is lit when the modem is communicating with the peripheral. | 
Hub
Hub status LEDs indicate the following:
| Green | A steady Green light indicates that the downstream (Type A) is powered on. | 
| Off | If the Hub LED is Off, it indicates that there is something wrong with the hub (drivers | 
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 | aren’t loaded correctly or the downstream device may have caused an overcurrent | 
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 | condition). | 
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 | Note: If the MT4X56USB is powered on but the USB cable is not attached, the Hub LED | 
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 | will be Off. When the USB cable is attached, the LED turns Green. | 
System
System status LEDs indicate the following:
| Red | A steady Red light signifies a loss of USB communication with the host. If the loss is due | 
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 | to unplugging the unit, it will begin blinking Red (before turning steady Green) when it is | 
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 | reconnected. A steady Red light also indicates a problem with the drivers (fixed by | 
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 | reinstalling the drivers). A blinking Red light occurs during software installation and will | 
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 | continue to blink Red until installation completes. | 
| Amber | Signifies serial port activity. | 
| Yellow | This LED may blink on and off during software installation until installation is complete. | 
| Green | A steady Green signifies that the serial ports have been successfully set up and the | 
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 | MT4X56USB is operating normally. | 
| MT4X56USB | 9 |