Dial-up Settings.
When setting up DTR for the first time, you may want to change the default dial-up settings. They can be found on the 'Settings/Register' tab. If you have an 'always-on' connection, and it automatically re-dials if the line is dropped, then you may leave both boxes unchecked. If the first box is checked, DTR will dial whenever there is no connection. If in addition to this the second box is checked, then DTR will hang-up ONLY if it initiated the dial-out in the first place. If there was already a connection to the internet, then DTR will not drop the line.
By default DTR will check your email every 10 mins, but you can choose from 7 mins upwards.
Also on the settings tab is the 'limit downloads per session' setting. The idea behind this that finding say 200 emails and replying to them all at once may burden your server/network. So if there are 200 emails, and the limit is set to 20, it will take the first 20 and wait until the next checking interval to get the next 20. This setting also affects how many delayed emails get sent on each session. If you are dealing with a huge number of emails and this number is set too low, DTR may never catch up, so use sensibly!
Actually if you are sending a lot of emails, you should probably use your own SMTP server rather than your ISP's - to keep them happy.