VBrick Systems EtherneTV MPEG-1, Руководство администратора

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38 EtherneTV Media Distribution System
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.
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:
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 de-asserted otherwise. The STB does
not use hardware flow control, so pins 6 and 8 (DSR and CTS) are not used. A null modem
DB9 cable (not included) with two female connectors can be used to connect the STB's serial
port to a PC.
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 RS-232 port will be a mix of characters
presented in the order they were received (e.g. the data from all the senders is bridged
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.
Pin Function
1 N/A
2 RD - Receive Data
3 TD – Transmit Data
4 DTR – Data Terminal Ready
5 Ground
6 DSR – Data Set Ready, not used
7 RTS – Request to Send
8 CTS – Clear to Send, not used
9 N/A