David,
Basically your 35mm provides  "switch closure" contacts to initiate
the flash.  The flash unit can cause significant current surges back
to the camera that can wipe out the camera electronics of any of the
TTL logic cameras which includes the 5700..  
The 5700 provides a TTL logic connection to CONTROL the flash unit. 
 The two are not compatible.
As to Nikons statement that "you must use their flash only", That's
BS.
However, should a future failure in your 5700 occur, and you admit to
using other flash units, it is possible that Nikon might not honor
their warranty
Many flash makers will state which flash models are compatible with
your 5700. Restrict yourself to ones that are compatible
John
On Mon, 24 Nov 2003 14:49:11 GMT, tuner92@hotmail.com (David) wrote:

>
>I have a Kalimar 175A flash unit which is used with my 35mm SLR
>(single contact on the hot shoe).  Is it possible to use this unit
>with my new 5700?   Nikon says, of course, that using anything other
>than their stuff will cause a nuclear explosion or something inside
>the camera.
>
>Any thoughts????  The Kalimar is just a standard 35 mm hot shoe unit,
>uses 4 AA batteries, ISO 100 guide number, etc.
>
>Thanks for any advice....David
>