How to disable the Dial-Upon-Lift feature

[Jeremy17]

Let's say I want to call 1-800-123-4567. Without lifting the handset, I start dialing "180". I then realize that the phone is really loud because it's playing the tones over the speakerphone, and potentially annoying my neighbors or a client sitting in my office. So I lift the handset to turn off speakerphone, and continue dialing. However, as soon as I lift the handset, the phone Sends "180" instead of letting me continue dialing the rest of the number.

How do I turn that feature off? I do not want the phone to Send the digits until I either press Send or wait for the dialing timeout. I do not want lifting the handset to instantly Send my partially dialed number.

Thanks.