From Cambridge website FAQ:

What are the differences between the S-NAV and the
L-NAV?

The S-NAV was designed in 1986 to do everything a pilot
might want in a gliding instrument. Its hardware and
software have been upgraded many times as we and our
customers learned what is useful. Building on 5 years
of experience, the L-NAV was designed in 1991 with
a simplified user interface to do what 90% of pilots
want 90% of the time.

The S-NAV supports two variometer displays. The second
display can be configured for 7 different functions.
The L-NAV has one variometer display.

The S-NAV has a high resolution, 12 bit A/D converter;
the L-NAV has a 10 bit A/D converter. This gives the
S-NAV the following extra capabilities:
An aerobatic g-Meter with ±10g range
Altimeter range of 0 - 36,000 ft. (L-NAV is 0
- 25,000 ft)
Electronic fine tuning of Total Energy Compensation


John Galloway



At 18:18 02 September 2004, John Sinclair wrote:
When we got the ASH-25, it had an S-nav, but no manual.
I saked Cambridge to send me a manual for S-Nav. They
sent me an L-Nav manual, saying everything was the
same. Does that answer your question.
:) JJ