I need some help on choosing the appropriate equipment (access points, antennas, cabling etc.) in terms of features, for an outdoor wireless link.

I would prefer reliability over speed, since the link is only for carrying a 1mbit/256kbit adsl connection.

The distance is 4km (2.5 miles) and I have line of sight.
Elevation at Point A is 118m (387ft) and at point B 28m (92ft).
The antennas will be mounted on flag poles.

If you need more information from me please ask.

Thanks in advance,

Kyriacos