asterisk users - May 2005 - Ericsson FCT f251m and polarity reversal

Hello,

This is a little off-topic. I have an Ericsson FCT f251m, according to
the specs it supports call signalling through polarity reversals and
loop break, but it's currently disabled.

On my PSTN line, my TelCo does send polarity switchs to signal answer
and hangup (answeronpolarityswitch=yes and hanguponpolarityswitch=yes
in zapata.conf), and asterisk detects it alright.

I've been unable to find an admin manual for this fct (or any of the
250 series). Can someone point me to the manual or just give me the
activation code to dial?

Thanks in advance,
    Julian J. M.