Gx series of CCD cameras are equipped with USB 2.0 interface with 480 Mbps transfer speed. USB interface brings numerous advantages beside the very high transfer speed. For instance USB connectors and cables contain also lines dedicated to provide power to attached devices, so the G0 and G1 cameras are connected to the host computer only by single cable (power requirement of the cooled CCD cameras of G2, G3 and G4 series is significantly greater than the USB line can provide and these cameras use their own power supply). USB cables are standardized, which is why they cannot be confused and plugged the wrong way etc. Also software support of USB devices is designed from the ground up to provide “Plug-and-Play” experience. Users need not to perform any device configuration, assign unique addresses etc.

A disadvantage of USB connection is the limited distance between a host PC and USB device. The maximum length of single USB cable is limited to 5 meters. This distance can be prolonged to 10 or 15 meters with the help of so-called Active USB Extenders, but a cable connection and active USB repeater (hub) must be placed every 5 meters. Very long USB connections can be also power-limited. The energy, provided by the host PC, is consumed by active repeaters and also long power lines with non-zero electrical resistance cause drop of supply voltage.

The problem of connection of Gx CCD cameras over a long distance is solved by Gx Camera Ethernet Adapter, offering remote camera connection over Ethernet interface. The core of the adapter is an embedded computer with a software is placed on the local Flash storage.

Three models of the Gx Camera Ethernet Adapters are available:

• The largest “standard” variant uses a PC-compatible motherboard equipped with the Intel Atom processor. No moving parts are present in the device, the processor needs no fan and is cooled only passively. This variant is powered by single 12 V DC line, the same like the G2, G3 an G4 cameras. Also power line connectors are the same, so the device can be powered like the rest of the setup.

• Medium variant of the Gx Camera Ethernet Adapter called “mini” is also based on the PC-compatible motherboard, but a smaller one called NUC (an abbreviation from Next Unit of Computing). These motherboards can have higher computational power and thus also higher TDP, so they can be equipped with a small cooling fan. Mini-variant of the adapter if powered from 19 V DC adapter (similarly to many laptop and notebook computers), supplied with the device.

• The smallest “micro” variant of the Gx Camera Ethernet Adapter is based on the ARM architecture. It is powered from a single 12 V DC line, like the standard variant (and like all G2, G3 and G4 cameras).

Regardless of different processors and in the case of Micro variant also different processor architecture, all devices employ multiple cores and at last 1 GB of on-board memory to be able to comfortably store full frames from even in the case all four connected cameras are the ones with the largest-resolution available. This is important to for the network connected device, because no isochronous data packet transfer and no delivery time can be guaranteed over a general network. Also all devices use the same software stack and are completely software compatible from the driver point of view.

The used Ethernet interface supports both 1 Gbps and slower 10/100 Mbps transfer speeds and it can be connected to all common local area networks. If the 1 Gbps interface is used and the download operations from multiple cameras do not overlap, the difference between download time of directly USB connected camera and camera connected over the Gx Camera Ethernet Adapter is negligible.

Device configuration

Every device providing services to clients over TCP/IP network must have a fixed IP address assigned to be continuously accessible. Configuration of the Gx Camera Ethernet Adapter network interface (assigning of the IP address, definition of the network mask and default gateway etc.) is performed using WWW interface. When the device is powered for the first time, the following parameters are preset:

To be able to connect to the device for the first time, it is necessary to attach it to the network with above defined parameters (it is enough to connect the device directly to the computer with properly set network parameters with an Ethernet cable). Then it is possible to connect the device to the desired network after the configuration is updated.

Configuration is performed through WWW interface and any web browser can be used to access it. The WWW configuration interface is not available all the time the device is running, but it is stopped after two minutes from the time the device is powered up from the security reasons. This measure prohibits unwanted configuration changes when the device is accessible from many different computers.

Connection over WiFi network

The Ethernet port of the adapter device can be attached to arbitrary WiFi bridge device to access attached cameras wirelessly. However, such solution needs another box (the Ethernet/WiFi bridge device) with another power supply etc. This is why the Gx Camera Ethernet Adapter firmware was extended with support for USB/WiFi interfaces.

The WiFi adapter can be plugged into any USB port. The Gx Camera Ethernet Adapter then can be added to any existing WiFi network.

Because the WiFi adapter antenna is located outside of the device metal case, the signal reception is better compared to devices employing WiFi adapter with antenna soldered on the electronics circuits board. The USB 2.0 HiSpeed transfer rate 480 Mbps typically do not bottleneck the WiFi transfers, which are usually slower.

Device with attached USB/WiFi adapter has to be configured over a wired Ethernet connection exactly like the standard Gx Camera Ethernet Adapter. However, the configuration page offers the WiFi adapter configuration section.

There are two possibilities how to assign the WiFi adapter IP address. The first possibility is to let the DHCP server assign it. Because the Gx Camera Ethernet Adapter is accessed as a server, it is necessary to assign a fixed address to it, so the clients always know the address to which they should connect. It is usually a task of the DHCP server configuration, which allows assigning a particular IP address to the device with defined MAC address.

Another possibility is to configure the IP address of the Gx Camera Ethernet Adapter manually.

The properly configured USB/WiFi interface can then be connect to WiFi network. The configuration page indicates successful connection.

Currently supported USB/WiFi chipsets are:

• Realtek RTL8192CU/RTL8188CU/RTL8187

  • ASUS USB-N10 Nano, USB-N13

  • D-Link DWA-121, DWA-131, DWA-135

  • TP-LINK TL-WN82xN

  • Netgear N150, N300

  • Belkin Surf USB Micro

• Ralink/MediaTek RT257x/RT2671/RT2770/RT2870/RT307x/RT3572

  • ASUS USB-N13, USB-N14, USB-N66, USB-N53

  • Linksys AE3000

  • Netgear WNDA4100

  • ZyXEL N220

  • D-Link DWA-137, DWA-140, DWA-160, DWA-162

• Atheros AR5007UG/AR2524/AR5523/AR5524/AR7010/AR9271

  • Netgear WNA1100li

  • TP-LINK TL-WN72xN

  • D-Link DWA-126

• Atmel AT76C50x

• Broadcom BCM43143/BCM43242/4320

• Marvell 88W8388/88W8797

Handling of the device

Standard variant

The standard Gx Camera Ethernet Adapter device can be powered from direct current power supply 8 to 19 V DC. Power connector is located on the left side of the unit back panel. The connector is standard 5,5/2,5 mm. Plus pole is on the inner pin, neutral (ground) pole on the connector outer jacket.

Universal 12 V DC AC/DC power supply is shipped with the Gx Camera Ethernet Adapter. The supply input voltage is 100-240 V AC/50-60 Hz.

Gx Camera Ethernet Adapter is configured to start immediately after power line is connected. However, it can be switched off and on when powered with the ON/OFF button on the device front panel.

Two more buttons RESET and FACTORY SETTINGS are also on the front panel. RESET reboots the device and FACTORY SETTINGS restores the default parameters (device configuration is described thoroughly in the following chapters).

Mini variant

The mini-variant of the Gx Camera Ethernet Adapter device is powered from 19 V DC power supply. Power connector is located on the side of the unit. The connector is standard 5,5/2,5 mm. Plus pole is on the inner pin, neutral (ground) pole on the connector outer jacket.

Universal 19 V DC/65 W power supply is supplied with the Gx Camera Ethernet Adapter. The supply input voltage is 100-240 V AC/50-60 Hz.

Gx Camera Ethernet Adapter is configured to start immediately after power line is connected. However, it can be switched off and on when powered with the ON/OFF button on the device top side.

Two more buttons RESET and FACTORY SETTINGS are also on the front panel. RESET reboots the device and FACTORY SETTINGS restores the default parameters (device configuration is described thoroughly in the following chapters).

Micro variant

The micro variant of the Gx Camera Ethernet Adapter device can be powered from direct current power supply 10 to 30 V DC. Power connector is located on the side of the unit. The connector is standard 5,5/2,5 mm. Plus pole is on the inner pin, neutral (ground) pole on the connector outer jacket.

Universal 12 V DC AC/DC power supply is shipped with the Gx Camera Ethernet Adapter. The supply input voltage is 100-240 V AC/50-60 Hz.

Gx Camera Ethernet Adapter is configured to start immediately after power line is connected.

Two more buttons RESET and FACTORY SETTINGS are also on the front panel. RESET reboots the device and FACTORY SETTINGS restores the default parameters (device configuration is described thoroughly in the following chapters).

Camera connection

Single Gx Camera Ethernet Adapter can attach up to four G0 to G4 cameras to the control PC using the Ethernet interface. It is worth noting that the device is not an ordinary USB/Ethernet converter, just tunneling USB data over the TCP/IP network (such converters usually do not work properly with all devices and their usage brings numerous problems and is not reliable). The Gx Camera Ethernet Adapter handles attached Gx cameras the same way like the host PC, there is no difference from the camera point of view in command sequences and especially timing, transfer speeds etc.

Quite opposite situation is on the control PC. There are fundamental differences between the camera connected directly to the USB port and the camera connected through the Gx Camera Ethernet Adapter. Cameras behave like two totally different and incompatible devices – the USB interface is used in the first case, TCP/IP network sockets interface in the second case (Gx camera and the Gx Ethernet Adapter behaves like a single device).

No USB device system drivers are to be installed on the control PC in the second case (and also system drivers for any other device are not installed), USB interface is not used to communicate with camera at all. The control computer communicates with the camera using the TCP/IP protocol only.

This is also why drivers for client programs (SIPS, ASCOM, MaxIm DL, …) are also different and a driver intended for camera connected to USB does not work with camera connected over Ethernet.

Let us note that unlike USB, the Ethernet interface (and TCP/IP network) is not designed to be “Plug-and-play”. If the connection to different computer (server) is to be established, its IP address or domain name must be known. So even before the control computer can connect to the Gx Camera Ethernet Adapter, the IP address or domain name of the particular device must be defined.

For instance every attached USB camera is immediately displayed in the SIPS (Scientific Image Processing System) software Camera configuration tool window and the user may choose the camera as imager or guider. And when no USB camera is connected, SIPS does not offer such cameras despite the camera driver is present and active.

On the other hand, cameras with Ethernet interface require the possibility to configure the IP address or domain name. This is why when the driver for cameras connected over the Ethernet is present in the SIPS, the software always displays a line “Gx Ethernet Adapter”, marked as “unconfigured”. When this line is selected, it is possible to open a dialog box allowing definition of IP address or domain name by clicking the “Configure” button.

Other programs may offer different ways to configure (define the IP address) the Gx Camera Ethernet Adapter.