How Passthrough Works
VBrick appliances are able to receive data on a particular TCP/IP port and transparently output that data to a serial port. Conversely, any data input to a serial port can be passed through to other devices connected to that TCP/IP port. Devices include other VBricks or special applications connected to the appropriate TCP/IP port. This feature is called "Serial Port Passthrough." COM1 is assigned port 4439 while COM2 uses port 4414. A typical application is for two VBricks connected to each other's TCP/IP port 4439. In this case, characters typed into a terminal program attached to one VBrick's serial port appear on a terminal program attached to the other VBrick's serial port. In this case, the TCP/IP network serves as an intermediary between the serial ports of two VBrick appliances.
You must select configuration settings to enable Serial Port Passthrough. First it is necessary to decide if the appliance will be designated as an Initiator or Responder of Passthrough connections. If configured as an Initiator it will continuously attempt to setup a Passthrough connection to other devices. When configured as a Responder it will accept up to 64 connections from Initiator appliances. It is possible to Disable Passthrough Mode, so that the VBrick neither initiates nor responds to Passthrough requests. If a VBrick is set to be an Initiator, a Destination must be selected. The appliance will use the destination information when trying to establish a connection. The destination can be configured as follows:
•Dedicated
•Remote COM1/COM2 using Slot1 Video endpoint
•Remote COM1/COM2 using Slot2 Video endpoint
•Slot1/Slot2 MetaData
Dedicated | means that the initiator will attempt to make a Passthrough |
| connection to the Dedicated Address and Port configured by the |
| user. Please note that the Dedicated Address Port configuration |
| parameters are used only when the initiator destination is set to |
| Dedicated. The Dedicated Address can either be configured using |
| IP Address or Host Name. The Dedicated Address Mode |
| parameter is used to specify whether the IP Address or Host Name |
| will be used. If the Dedicated Address Mode is set to Host Name, |
| the Dedicated Address is configured using the Dedicated Host |
| Name parameter. Likewise, if the Dedicated Address Mode is set |
| to IP Address, the Dedicated Address is configured using the |
| Dedicated IP Address parameter. |
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Slot1 Video Endpoint | use address information that is configured for the device in that |
Slot2 Video Endpoint | slot. If the device in that slot is an encoder, the initiator will |
| attempt to establish a Passthrough connection to the unicast |
| Destination IP Address configured as Destination 1 for that slot. |
| Note: Passthrough is supported using Destination 1 only; |
| Destination 2 has no meaning for the Passthrough operation. If |
| the device is a decoder, the initiator will attempt to establish a |
| Passthrough connection with the address configured as the |
| Decoder Receive IP Address and Port. The receive address can be |
| either multicast or unicast. |
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28 | © 2008 VBrick Systems, Inc. |
