Stealth Serial Port

Be sure to see the sections called "How to Install" located on the info pages of Stealth and Slick before contacting Gee Three.


Frequently Asked Questions - Stealth Serial Port

What is the Stealth Serial Port and what does it do?

The Stealth Serial Port provides a standard serial port for new Macintosh systems that lack a built-in serial port. It works with virtually any serial peripheral, including MIDI devices, LocalTalk printers, and video tape decks for deck control. There are versions for the G4 (2001-4 PCI Slots, Dual processor and AGP), Blue & White Power Macintosh G3 and iMac (Rev. A-D).

How compatible is the Stealth Serial Port?

The Stealth Serial Port is designed to be compatible with all serial devices that work on older Mac systems. The Stealth Serial Port's interface card uses the same chipset found on earlier Power Macs. It is compatible with serial printers, modems, MIDI devices, LocalTalk printers, deck control software and more. No new drivers are required other than the Stealth Serial Port extension. A standard Mini-DIN8 connector is provided out the back of your Mac. The Stealth Serial Port also comes with a 30-day money back guarantee.

Does the Stealth Serial Port work with Mac OS X?

The Stealth Serial Port provides the same level of compatibility under OS X as a built-in serial port on a beige G3 running Mac OS X. Click here for more details on Mac OS X.

External modems work fine by configuring the serial-port in the Network System Preference. We're working with application developers creating OS X applications to access the Stealth Port. Also, Apple has stated that some things such as LocalTalk will not be supported in OS X.

What is the latest version of the Stealth extension?

The latest version of the Stealth Serial Port extension is version 1.03. This version fixes a problem with Mac OS 9.0.4 and LocalTalk. While it is not required for earlier versions of the Mac OS or for non-LocalTalk uses on Mac OS 9.0.4, it works fine with those configurations.

How do I use the Stealth Serial Port?

The Stealth Serial Port appears as a standard serial port to all applications. For applications that use the Communications Toolbox, just select the Stealth Serial Port. This includes Palm Pilot connection kit 2.0, most communications programs, and many print drivers. For other applications, just select the Modem port.

What are the system requirements for the Stealth Serial Port?

The Stealth Serial Port requires an empty modem slot for the Stealth Serial Port card. This slot is required to achieve the most robust and reliable serial compatibility possible. Since the Stealth card replaces the internal modem card, if you need a modem you will need to use an external modem. Your system must be a G4, Blue G3, or iMac Rev. A-D system.

How much does the Stealth Serial Port cost?

The Stealth Serial Port is available for $49.95 plus shipping and handling.

My system came with an internal modem. Can I still use a Stealth Serial Port?

The Stealth Serial Port fits in the internal modem slot of the G4, Blue & White G3 and iMac. If your system came with an internal modem, it must first be removed before the Stealth Serial Port can be installed. The Stealth replaces the internal modem, so if you need a modem you will need to use an external modem.

Does the Stealth Serial Port work on the new G4 systems?

Yes, there is a new model of the Stealth Serial Port latest G4-2001 (4 PCI slots, 133 MHz. bus) systems. This model is backward compatible with earlier G4 systems (except G4 Yikes - PCI video). Older versions of the Stealth Serial Port will not work on these newer machines.Some of the earliest entry G4's models used the same logic board as the Blue & White G3. These system require the Stealth for the Blue & White G3. We have created a chart to help you determine what type of G4 you have.If you have an early model of the G4 Stealth Serial Port, the Stealth card may not fit in the Dual Processor G4 (3 PCI slot, 100MHz bus) systems. But you can make a simple modification that will not impact any functionality.

How does the Stealth Serial Port compare to USB-to-serial adapters?

The Stealth Serial Port provides a "native" serial port on the G4 and G3 systems, just as if they had a built in serial port. This gives it unsurpassed compatibility and reliability compared to any of the USB-to-serial solutions. The Stealth is the choice for professionals that require their serial device to "just work", without concerns for compatibility, extension conflicts and reliability.USB-to-serial adapters have a much more limited range of serial devices they support. They do not work with LocalTalk or MIDI devices. They also are compatible limited range of printers. And their software may conflict with other system resources.As an internal adapter, the Stealth has a very clean installation without "dongle" hanging outside your system.Finally, if you do have questions about your Stealth Serial Port, also offers excellent technical support by ending support questions to

Does the Stealth work with MIDI and deck control software?

The Stealth Serial Port works great for these uses. Apple and the major software and hardware vendors recommend the Stealth as the serial connectivity solution for MIDI and deck control.Here are some hints to help get your MIDI setup going:

  • If you are using OMS, set the configuration to communicate via the modem port. If you are using FreeMIDI, configure it to use the Stealth port.
  • When you configure your MIDI software, it should scan through a list of devices. If not, reinstall the MIDI software as it requires support files in specific locations.
  • Reset Parameter RAM. Boot your system and hold down the option-command-P-R keys.
  • Check to see that the Stealth card and cable are securely attached.

For deck control uses, such as with Final Cut Pro, the most common problem is that a special type of serial cable is required to communicate to the tape deck. The standard printer cable generally will not work. Please contact us at and we'll help you find the correct cable .
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How do I install the Stealth Serial Port?

The Stealth Serial Port installs in minutes with just a screwdriver. Just open the G3/G4, unscrew the metal plate covering the modem hole, plug in the controller card and screw in the mini-DIN8 connector. If you can install memory into a Blue & White G3, then you can install a Stealth Serial Port.

Will the Stealth Serial Port work if I have an internal modem card installed?

Unfortunately, no. The internal modem card and the Stealth Serial Port's interface card use the same slot on the motherboard.

Does the Stealth Serial Port take up a PCI slot?
The Stealth Serial Port is installed in the same place as an internal modem card. This leaves all of your PCI slots open for other uses.
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How do I connect more than one serial device to the Stealth Serial Port?
The Stealth Serial Port has one mini-DIN8 serial connector. We have found that manual switch boxes are the best solution to connect multiple serial devices to the Stealth. Although you can only use one device at a time, it is much easier than reaching behind your Mac to change cables are there are no software compatibility issues. We offer the ThreePort manual 3-way switch box available for $20.
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Can I use a LocalTalk printer and Ethernet network connection at the same time without switching AppleTalk connections? Can I use Apple's LaserWriter/LocalTalk Bridge software on a G3/G4 and Stealth?
If you are using Ethernet only for an Internet connection (f using a DSL/cable modem via TCP/IP), you can have AppleTalk set to the modem/printer port to communicate to a printer without switching any settings.
If you are using AppleTalk over Ethernet (to communicate to files servers or network printers), Mac OS 8.5 and later supports one AppleTalk connection at a time in the AppleTalk control panel. However, Apple's LocalTalk Bridge software provides the capability to use AppleTalk over Ethernet and the modem port at the same time. According to Apple's Tech Info Library, this bridge software is not fully compatible with Mac OS 8.5 and later (and thus, a Blue G3 and G4). has created a software patch for the latest release of the Bridge software from Apple that works, with certain limitations, with the Stealth Serial Port. Click here to find out more about Apple's LocalTalk Bridge software and the patch.
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Does the Stealth Serial Port support 230.4K data transfer rates? Does it work with Apple's two-machine debugger?

Yes, the Stealth Serial Port supports the faster 230.4K data rates. It also works with the two-machine debugger.

How does it work on the iMac? Why do I have to remove the internal modem?
The Stealth Serial Port for the iMac has the same functionality as the version for the G4 and Blue G3. To achieve the high level of compatibility, it interfaces with the modem slot on the iMac logic board. This, unfortunately, requires the removal of the internal modem. Also, it is recommended that a dealer or certified technician install the Stealth Serial Port for iMac.
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How can I tell what revision iMac I have? Does the Stealth Serial Port for the iMac also work on the new iMac DV?
The Stealth Serial Port for the iMac works on revisions A-D of the iMac. This covers all models of the iMacs (including the flavors) with processor speeds from 233MHz. to 333 MHz.
The new iMac DV and iMac - 350MHz. are based on a new logic board. The modem slot on these machines is very difficult to access and the hole for the modem jack is not large enough to accommodate a serial port. Sorry.
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What serial devices don't work?

Through our extensive testing we have not been able to find just a few devices that do not work with the Stealth Serial Port.

  • If you are using either the StyleWriter II and StyleWriter 2500 print drivers please contact for a special version of the Stealth extension for those printers.
  • Any device that requires a 9-pin mini-DIN connector. So if you want to use an old GeoPort modem or other device that draws power from the extra pin, it will not work with the Stealth Serial Port.
  • LaserWriter Select 310. Apple dropped support for this printer in Mac OS 8.5 so it does not work with any of the newer Macs. For a workaround, please check:
  • QuickTake 150 . The QuickTake software for this camera does not access serial ports correctly. Sorry.
If you are using a Newton, we have found that connecting via LocalTalk works much better. back to top

How do I contact Gee.Three for other support questions?

For other support questions, please send an email to and we will get back to you quickly.

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