TeleTone allows you to dial contacts & phone numbers by playing the touch-tones digits on the iPhone internal speakers (and attaching it to the landline telephone handset microphone).
This allows you to make calls using your landline phone when youre in the office or at home.
You can also use it to send DTMF sequences to IVR, Voicemail and other automated systems.
TeleTone uses the same methods used by TAKEphONE-i to search your contacts database in a fast and super easy way (using a T9-like on screen large keypad - so to find "John Doe" all you need to press is "5 jkl" then "6 mno"...).
Important note: If you like the way TeleTone lets you find contacts and manage them, but want to actually call them using the iPhone - get TAKEphONE-i.