Eusebius wrote:
Does anybody know if I can dial a number and then enter a code? Since
I'm using my landline the keypad on the telephone should be
functional, I hope!

Ah, you mean while the call is in progress you can send a DTMF (touch)
tone from your handset keypad. Yup, shouldn't be a problem doing that
through 1899.com

On Skype this is also possible. Enter the following in the help search
on Skype.com "How do I dial an extension" which will show you where the
touch tone pad is hidden.

--
Adrian C