For a customer with their own custom device that uses an unused resistor value, they can make the following registry entries to have our terminal "recognize" their device, and activate their supplied device driver. (I will use angle-brackets to denote the customer-supplied data... eg. <string>)

[HKEY_LOCAL_MACHINE\Services\TekDTSvc\TetherPort\<resistor-value>]
    "FriendlyName"="<string>"
    "Dll"="<DLL-filename>"	; optional device-driver to activate
    "Power"=dword:<0|1> ; 0 = no power, 1 = requires power
    "ConfigTether"=dword:<0|1|2|3> ; 0=no configuration, 1=serial device, 2=non-decoded scanner, 3=USB device
    "Icon"="<file,-index>"	; 32x32 colour icon to display in the UI when device is connected
    "IconBW"="<file,-index>"	; 32x32 black/white icon
    "SmallIcon"="<file,-index>"	; 16x16 colour icon to display in the tray while device is attached
    "SmallIconBW"="<file,-index>"	; 16x16 black/white icon
    "Order"=dword:<value>		; required by device-drivers, but unused in this case
    "Prefix"="<3-letter-prefix>"	; 3-letter device-driver prefix (such as "COM", used for serial ports)
    "IClass"=multi_sz:"{CLSID}"	; optional notification CLSIDs, for example, if the device-driver needs power-notifications (developers should refer to the CE.NET docs)
[HKEY_LOCAL_MACHINE\Services\TekDTSvc\DockingPort\<resistor-value>]
	; uses same registry values as above, except for "ConfigTether"

The above "ConfigTether" configuration values:

0 = no configuration
1 = serial device
2 = non-decoded scanner
3 = USB device