FXCodeBase.COM: Forex Chart Indicators and Development

Hi,
I am writing a custom strategy using bollinger band. Are the following right?

BB.BL[period] gives the value of the bottom line for the period.
BB.TL[period] gives the value of middle line (trend line) for the period.
BB.AB[period] gives value of the top line for the period.

suppose if i want to place an order when the bar goes above the middle line for example,
i should do

src.close[period] >= BB.TL[period}

Is this right?

I'm not sure which BB you are using.

For standard BB, We have TL, BL and AL.

For central line crossover, will have something similar.
if source.close [period]> BB.AL [period]
and source.close [period-1] <= BB.AL [period-1]
then
end

--and source.close [period-1] <= BB.AL [period-1] is optinal.

Can someone explain in Bollinger band, what TL, AL, BL are? Which is the central (middle ) line, and standard deviation lines (bottom and top lines). This is not clear to me.

Can you please tell me about AL,TL and BL. Is my interpertation right about them as mentioned in my previous message?

AL is the middle line at the BB chart, which is N periods of MVA ( default N is 20).
TL is the the top line at the BB chart, which is AL + M multipled by the standard deviations. (default M is 2)
BL is the the bottom line at the BB chart, which is AL - M multipled by the standard deviations. (default M is 2).