This will prevent the Envisage application from sending simultaneous "North and South" ON commands (or simultaneous "West and East" ON commands) to the ST4 lines.
MEADE AUTOSTAR VOLTAGE SOFTWARE
Users of the Meade Envisage and Guidestar version 1.0 and 1.1 LX200 Emulator software using the Meade DSI, DSI Pro, DSI-II, LPI as autoguider cameras, you need to click the radiobutton "1 at a time per axis" option (found at the left side portion of the guidestar window) during the autoguide sequence. Printer I/O port no longer hardcoded, but is selectable for all possible printer port IO address (LPT1: &H378, LPT2: &H278, LPT3: &H37B) If you wish to guide using USB, make sure GPUSB is connected to the PC's USB port prior to executing the software. To select between GPUSB and the printer port, just select the interface type prior to clicking the start button.
MEADE AUTOSTAR VOLTAGE MANUAL
For the other details refer to the GuideStar 1.0 manual below.
Aside from the standard printer port interface (LPT1 to LPT3), it is now possible to guide your ST4 compatible mount using USB.
MEADE AUTOSTAR VOLTAGE UPGRADE
GUIDESTAR Version 1.1 is an upgrade of GUIDESTAR 1.0 with the addition of Shoestring Astronomy's GPUSB/GPINT-PT support. Which means a North + West or North + East (South + East or South + West) can still function even if the one at a time per axis option is enabled. Each axis is still treated independently by the application. This option will block simultaneous North and South correction commands (or West and East correction commands). Starting Guidestar 1.0, an option called "1 at a time per axis" is provided to process this condition in order to allow the mount to handle the last autoguide command sent. Some mounts will not be able to handle this. Some autoguiding application sometimes enable both North and South at the same time (or East and West at the same time). The ST-4 (GPSUB/Parallel port ) correction lines are disabled internally by the guidestar application depending on the defined pulse duration. RA+/DEC+/RA-/DEC- OFF correction commands are ignored if the corresponding axis pulsewidth override is enabled. The pulsewidth override function can also be used on the non LX200 GPS mode. Possible values could be anything between 50 milliseconds to 5000 milliseconds (5 seconds). Slide the horizontal bar to define the pulsewidth on each axis. The user also has the option to override the duration parameters by enabling the "RA/DEC Pulse Width Override" options. Mexxxx, Mwxxxx, Mnxxxx, Msxxxx, where "xxxx" are correction pulse width in milliseconds. Just enable the "LX200GPS Mode" option button prior to connecting the autoguiding program and all commands will be processed as an emulated LX200GPS pulseguide commands Guidestar Version 2.0 now supports LX200 GPS Pulse Autoguide Method. GUIDESTAR LX200 Emulator Software Version 2.0