Be very (!!) careful when you use this driver.

It is designed to give the remote user full control of the telescope. This
means it is the end-user's responsibility to insure that the telescope does 
not move into a configuration that may damage it, or damage accessories
attached to it.

A German equatorial is particularly susceptable to collision with the pier, or
with "hard stops" on the mounting.  This driver does take these limits into
account, and attempts to keep the telescope away from the pier.  However, it
is possible that something could go wrong, and the NexStar control system
does NOT provide for full safety.

If you are using this system to control an unattended telescope, I strongly
recommend that you add mechanical switches in series with the DC supply on
the motor drive.  These switches would be normally closed, but should
instantly open if

(1) OTA points below the horizon
(2) The HA motion exceeds the mounting's physical limits
(3) The Dec motion endangers attached accessories such as the camera

The OTA switch could be a level switch. These are typically simple
ball-in-tube devices that trip a microswitch if the ball is at the bottom of
the tube. Mercury switches are also ideal, but not environmentally sound.

The HA limit switches should be mechanical (not software) microswitches that
trip when the mounting approaches its HA slew limits.  On a fork mount this
may not be necessary.  On a German equatorial it is essential to protect
against accidental collision of the OTA with the pier.

The Dec limit switch is necessary on a fork mount if attached cameras or
accessories cannot clear the inside of the fork.  Some protection is
provided by the OTA level switch, but this is not complete.

Recovery from a limit switch trip should require manual intervention. In a
remote system with visual confirmation of the telescope's orientation, this
may be met by a power override on the telescope CPU, followed by manual
control of the telescope slew to clear the limit situation.

Suggestions and examples of how to achieve this inexpensively will be
provided in the manual and on-line documentation eventually.  In the
meantime, regard this driver as experimental, and use it with the
understanding that there are risks.