As part of a project I have been working on to spec and install a video conferencing solution I purchased a couple of Startech VS421HDPIP units to switch between camera inputs. I chose this unit for a couple of reasons; it has enough inputs for the project, it’s capable of doing picture in picture, it can be controlled via telnet or RS232, our supplier could get it for half the RRP and it’s made by Startech, who’s kit has never left us in an awkward situation.
When I first hooked it up it just worked and the presets that were built-in were decent. Unfortunately it didn’t have presets to support the use cases I required, but I expected that from reading the manual prior to purchasing them. The presets can be changed from the web interface, which is the only downside to this unit… its utter pants. Fortunately it supports some pretty advanced commands via telnet so all is not lost. After playing with the telnet prompt for a while I figured that I could probably write some form of application to change the video output layout from a PC, which would certainly make it more user-friendly. The VC solution is going to be installed in a remote office and anything to make operation easier for the end users is a big plus. This will also allow me to have basically unlimited “presets” to cover more use cases without reconfiguration. Bonus.
Driver
I decided that the application should probably allow control of the PTZ cameras too to encompass the entire VC solution in one control panel, so a simple “driver” style API would be the best bet for controlling each component. The driver for the Startech VS421HDPIP only took two hours to write, including an application to test the class, and is incredibly simple to use. It is available to download at the end of this post. Here’s an example of how to use it.
//create a new instance of the VS421HDPIP class.
VS421HDPIP Conn = new VS421HDPIP();//set the unit IP address and port
Conn.Ip = IPAddress.Parse(“192.168.1.6”;
Conn.Port = 23;//open the connection to the unit.
Conn.Open();//execute commands. See list of commands in the accompanying blog post.
Conn.PowerOn(); //Power on the unit from standby
Conn.Recall(VS421HDPIP.WindowState.Fav1); //Recall the Fav.1 Preset
Conn.SetImagePosition(VS421HDPIP.InputChannel.Input2, 1420, 790); //Sets the possition of channel 2.//always close the connection when done. The unit only allows one session at a time and not closing a session will result in you having to reboot the unit or waiting for the session timeout on the unit before opening a new connection.
Conn.Close();
Unfortunately the telnet prompt doesn’t let you retrieve information. Maybe this is something Startech will add to future models but it is what it is.
Commands
The commands I implemented are basically identical to the commands listed in the manual for the VS421HDPIP. I won’t go over available parameters for each here. The parameters are similar to those listed in the manual as well so I’m sure they’d be easy to figure out with intellisense.
- PowerOn() – Power on the unit from standby.
- PowerOff() – Place the unit in standby.
- SetOutResolution(Resolution res) – Sets the output resolution.
- OsdDisable() – Disable the On Screen Display.
- OsdEnable() – Enable the On Screen Display.
- OsdHOffset(int offset) – Sets the horizontal offset of the OSD.
- OsdVOffset(int offset) – Sets the verticle offset of the OSD.
- OsdTimeout(int timeout) – Sets the timeout of the OSD.
- OsdGain(int gain) – Sets the gain of the OSD.
- SetBrightness(InputChannel chan, int level) – Sets the brightness level of an input.
- SetContrast(InputChannel chan, int level) – Sets the contrast level of an input.
- SetSaturation(InputChannel chan, int level) – Sets the saturation level of an input.
- SetHue(InputChannel chan, int level) – Set the hue level of an input.
- Mute() – Mutes the audio output of the unit.
- Unmute() – Unmutes the audio output of the unit.
- SetImageSize(InputChannel chan, int h, int v) – Sets the size of a channel.
- SetImagePosition(InputChannel chan, int h, int v) – Sets the position of a channel.
- ChannelImageOn(InputChannel chan) – Turns a channel on.
- ChannelImageOff(InputChannel chan) – Turns a channel off.
- ChannelPriority(InputChannel chan, int priority) – Sets a channel’s priority.
- SetChannelLabel(InputChannel chan, string label) – Sets a channel’s label.
- StoreCurrentConfiguration(Favorite loc) – Stores current settings to a preset.
- MirrorOn() – Makes the unit mirror it’s output (rear projection).
- MirrorOff() – Disables the output mirror feature.
- SetOutputRotation(Rotation value) – Rotate unit output (ceiling hung projector).
- SetFadeDuration(Fadetime time) – Sets fadetime between windows.
- SendTelnetCommand(string command) – Send a telnet command to the unit.
Download
I have provided the driver I wrote in case it is useful to anybody. I do so with absolutely no warranty or support and you use it at your own risk.
Dan McIntyre 