For example, a generic Telnet client configured to connect to an STB on port 4439 will cause the STB to start sending data from it's serial port, using the connection it accepted from the Telnet client.
Note Once a Passthrough connection is established, the actual flow of data is symmetric between the ends of the connection. That is, the behavior of the serial ports with respect to typed characters will appear to be the same at both ends, Initiator and Responder.
Serial Port Pinouts
The serial port on the STB can be used for device management or for the passthrough responder feature. The pinouts on the serial port are listed below:
Pin | Function |
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1 | N/A |
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2 | RD - Receive Data |
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3 | TD – Transmit Data |
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4 | DTR – Data Terminal Ready |
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5 | Ground |
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6 | DSR – Data Set Ready, not used |
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7 | RTS – Request to Send |
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8 | CTS – Clear to Send, not used |
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9 | N/A |
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The RTS and DTR pins can be configured to be always asserted, never asserted, or "auto." When configured for auto, the control leads are asserted when a passthrough initiator has established a connection to the passthrough port and
Using Telnet
As noted, the serial port can be accessed over Ethernet via a Telnet client. An STB configured as a Passthrough Responder will accept a connection request to TCP port 4439. The request can come from a Telnet client or other PC application. Any data sent by the PC to TCP ports 4439 will be delivered out of the STB serial port and any data present on the STB serial port will be sent to the connected PC.
If multiple Telnet sessions are active on one STB (each STB supports up to 64 sessions), the data from the STB will be sent to all connected PC's, and the data received by the STB from the PCs will be delivered on the serial port. If multiple Telnet sessions are active and each is sending data to the STB, the data delivered by the
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