Serial / USB Mount to Computer Connectivity
Devices, Adapters and Cables

Astro-Physics is delighted to offer products from Keyspan by Tripplite, and Icron Technologies that provide connectivity between our GTO mounts and today’s PC's and laptops which rarely have genuine serial ports any more. Let us start out by stating emphatically that we are NOT a computer company. We are not the Microsoft® Help Desk, and we cannot make any guarantee that we can solve any and all issues that may arise as you try to communicate with your mount via an external computer. That being said, however, we have found these products to be reliable, easy to set up and configure, and an excellent value. The Keyspan and Icron units work well with Windows® machines and with MacOS® systems, and they all offer superior customer support. Furthermore, there is even support for the LINUX® operating system for the Icron USB Ranger® and most of Keyspan’s products.

The USB to Serial conversion devices by Keyspan are all backward compatible and fully upgradeable. They employ the latest chipsets from Texas Instruments, which include re-programmable ROM. The separate drivers for Windows, MacOS and LINUX are kept at the most current level and the driver software will update the device's ROM as needed. We strongly advise that you check the Keyspan website often for the latest in driver updates to ensure continued high performance and top level compatibility.

The Icron USB Ranger is the latest in a long line of USB devices designed to overcome the 5 meter limitation of conventional USB. Think of it as the ultimate USB extension cord that can provide up to 100 meters of separation with no loss in speed or performance!

Some of the text below is taken directly or mostly from the Keyspan and Icron websites, and is obviously geared toward the general public. In the paragraph(s) that follow the bulleted points from Keyspan, we have made some commentary from our own personal experiences that relate directly to astronomy uses in general and to Astro-Physics GTO mount operations in particular.

Keyspan™ USB to Single Port Serial Adapter (USB1P)

This is the easiest way to connect a single serial device to a USB port on your PC or Mac. The Keyspan USB High Speed Serial Adapter provides a simple and reliable solution. This adapter is broadly recommended by serial device manufacturers due to its dependability and broad compatibility.

Features include:

  • Certified: Microsoft® WHQL approved
  • High Speed: Supports 230 Kbps - twice the speed of a built-in serial port
  • Detachable Cable: Use adapter with any USB cable (up to 15 feet long)
  • 3 foot long USB cable included.
  • LED: Shows adapter status and data activity
  • Plug & Play: Appears as standard COM port
  • Mobile: Easy to carry - weighs just 2 oz.
  • Bus Powered: No external power-adapter required
  • Analytic Tools: Includes Windows® line monitor and data trace software
  • Field Upgrade: Easy to update over time with free software downloads
  • Easy Expansion: Supports use of multiple adapters on one PC
  • Lead Free RoHS compliance

This was the first Keyspan unit that we tried here at Astro-Physics. It worked right out of the package on the Windows XP machine in the Technical Support office. Loading the drivers from the included CD was a no-brainer. We simply accepted the defaults and it all performed flawlessly. Connections to a mount with PulseGuide™ and The Sky 6™ Professional software packages were totally routine and uneventful. We even re-programmed an Astro-Physics keypad, again without a hitch. Next, the adapter was tried on a laptop running the Vista® OS. As hard as it may be to believe, that also went smoothly. Finally, the USB / Serial Adapter was tried on a Mac Powerbook® G4 running OSX. There were no issues, and we were soon controlling a mount on the Mac with Starry Night Pro Plus™ planetarium software.

An extremely handy feature of both this adapter and the 4-port adapter below is the Serial Assistant. This is not only helpful in establishing which COM port number has been assigned to the adapter, but the Data Monitor Window is a great tool for diagnosing problems with software that you may be using to control your mount or other devices.

Basically, if you only need to use one of the mount’s COM ports for such things as keypad firmware upgrades, or to occasionally use software like The Sky or Starry Night Pro Plus planetarium programs to control the mount, then this is the adapter for you. Two of these adapters will also work together without problems if you want to use both COM ports (for example to run both PulseGuide and The Sky) and if you have two available USB ports on your computer.

Please Note: This device does not attach directly to your GTOCPx Control Box. A straight-through serial cable like our CABSER15 is still required to make the connection.

USB1P$43.00 in stockAdd USB1P To My Cart

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Icron Ranger® 2304 USB 2.0 Extender – Four-Port (USBIEXT4P-2304)

The USB 2.0 Ranger® 2304 is a four port USB 2.0 high speed extension solution, enabling USB 2.0 connections at up to 480Mbps over 100m/330ft of Cat 5e (or better) cabling, without the need of additional software drivers. A true plug-and-play solution, the Ranger 2304 is compatible with all leading operating systems, and supports all USB 3.0, 2.0 and 1.1 peripherals such as flash drives, keyboards, mice, webcams and interactive whiteboards across a dedicated Cat 5e connection.

The Ranger 2304 is the latest USB 2.0 extender system from Icron, offering the same reliable USB 2.0 extension benefits as the Ranger 2204, but with faster throughputs when using read/write devices such as external hard drives as well as supporting a greater number of connections (up to 31 devices and hubs). The Ranger 2304 provides an integrated four port remote USB 2.0 powered hub delivering 600mA to each port


  • Extends USB range up to 100 yards/330 feet
  • USB Device Support:
    • Traffic Types: All USB 2.0 and 1.1
    • Device Types: All USB 3.0, 2.0 and 1.1 devices
  • Supports all USB devices up to 480Mbps
  • True plug and play. No drivers required
  • Supports all major operating systems: Windows®, Mac OS X®, and Linux®
  • Uses a standard solid core Cat 5e (or better) cable for easy installation
  • Number of devices can be increased using additional USB hubs
  • FCC Class B
  • Rugged metal enclosure  

Note that the remote unit requires power for proper operation (included AC power adapter is 24 volt DC output). Astro-Physics stocks units with the North American standard power adapter. UK, European and Australian adapters are available by special order and may require a small surcharge.

Icron USB Ranger® 2204 Data Sheet (PDF)

USB Ranger 2304 System Includes:

  • Local extender unit (LEX)
  • Remote extender unit (REX)
  • 2 meter USB 2.0 cable
  • AC power adapter
  • Two year warranty from manufacturer

More distantly remote observatories (over 100 yards/330 feet from the controlling computer) will generally require a computer or IP addressable server in the remote observatory itself, and a high speed internet connection for communication with your home computer. Such solutions are beyond the scope of Astro-Physics to supply or support.

Note: A Cat 5e (or better) cable is required for use (not supplied).

USBIEXT4P-2304$375.00 in stockAdd USBIEXT4P-2304 To My Cart

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15 Foot Straight-through, RoHS-compliant Serial Cable (CABSER15)

You would think that a serial cable would be a straight-forward simple device that would be confusion- and mistake-proof. This is unfortunately not the case. The most common source of computer / mount communication failure is the wrong cable! There are straight-through cables and reversing cables. The reversing cables are also called crossover cables, null cables, modem cables, and null modem cables just to add to the confusion. Then there is every possible configuration of male / female plug - with locking screw or nut, without locking screw or nut. Many are not even labeled as to their orientation. (Maybe it isn't considered politically correct!) It is simply ridiculous. And the flunky at the big box computer store is no help.

Your mount MUST be connected with a straight-through cable. Straight-through cables are wired with the corresponding numbered pins of the connector wired to each other: pin #1 on the male end to hole #1 on the female end; #2 to #2 and so on. Other serial cable types cross or reverse some of the wires making communication with your mount impossible.

We have found a source of genuine standard straight-through serial cables and selected these 15 foot cables as the most universally appropriate. They have molded connectors, are fully shielded, and are lead-free for RoHS compliance (and all-around environmental friendliness). They also employ gold-plated contacts for superior data retention and corrosion resistance. They can even be used for monochrome or CGA/EGA monitor cable extension. Finally and most importantly: They actually work, and you don't have to drive all over town to find one! Need we say more?

CABSER15$15.00 in stockAdd CABSER15 To My Cart

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This page was last modified: May 14, 2014

Astro-Physics, Inc.
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