Arrive in time/Arrive on time

What is the difference between " to arrive in time?" and " to arrive on time"?
To arrive on time <-------->準時到達 ( to imply you are not late)
Examples:
I thought you would be late for the meeting, but you arrived on time.
( You arrived at the meeting ( about the fixed time) just right before the meeting started. )
________________________________________________
To arrive in time ------------>及時到達 ( It has something to with the EXACT FIXED TIME or ( about some bad situations)
1) My school begins at 8 :30 am. <-------I thought I would be late when I was in Mong Kok at 8 am. Fortunately I arrived ( there just )in time.及時到達 ( ARM ARM HO @(*J*)@)
2) The firemen arrived in time to save the people. ( bad situation)
The time is not stated here. <--------------------沒有講 時間
It means " the firemen arrived at the scene before the fire killed those people".



2009-01-09 14:30:44 補充：
It has something to do with the EXACT FIXED TIME

in time的中文解釋是及時，而on time是準時；它們的分別是及時不一定是準時，如，你約了朋友５時在戲院見面，一起去看５：３０的戲，結果，你５：２０分才到，雖不準時，但卻趕得及看戲。
You did not arrive at the cinema on time, but you were in time for the moive.
而且你要留意，in time是相對於某事／或做某事來說；而on time是相對於時間來說。

希望幫到你！

arrive in time > arrive at that time sharp
arrive on time > arrive around that time

Sample:
You have an appointment at 3:15pm and you arrive exactly at 3:15 sharp, then you arrive in time, and if you arrive at 3:14pm or 3:16pm, then you arrive on time.

Since we don't expect people meet an appointment at a particular time spot exactly, therefore, usually we say 'arrive on time' instead of 'arrive in time'.

2009-01-12 12:08:15 補充：
After look up the dictionary and refer to the other's answers, the answer that I posted here is WRONG. Since marks will be deducted if I delete it, so I leave it here. Sorry about that!

Arrive in time
係及時到達
Arrive on time
係準時到達