Editing Red box (phreaking) (section)

===United States===
The tones are made by playing back 1700&nbsp;Hz and 2200&nbsp;Hz tones together.<ref name="Lapsley2013">{{cite book |last=Lapsley |first=Phil |author-link=Phil Lapsley |date=2013 |title=Exploding the Phone: The Untold Story of the Teenagers and Outlaws who Hacked Ma Bell |url=https://books.google.com/books?id=ECiBd4mYkVwC |publisher=Grove Atlantic |pages=239–241 |isbn=9780802193759}}</ref> One 66 [[Millisecond|ms]] tone represents a [[Nickel (United States coin)|nickel]]. A set of two 66 ms tones separated by 66 ms intervals represent a [[Dime (United States coin)|dime]], and a [[Quarter (United States coin)|quarter]] is represented by a set of five 33 ms tones with 33 ms pauses. A single 650 ms tone represents a dollar,<ref name="347gr506">{{cite book |date=1996|title=GR-506-CORE: LSSGR: Signaling for Analog Interfaces |publisher=Bellcore |page=249}}</ref> but this is rarely used.
{{Listen|filename=Redboxquarter.ogg|title=USA Red Boxing Tone|description=The .25 USD tone sequence.|format=[[Ogg]]}}

The system that handles these tones is called the Automated Coin Toll Service, or ACTS. However, since ACTS has been phased out of service in much of the United States, combined with the integration of acoustic filters into many payphone handsets, the practice of red boxing is rarely possible any longer.
<!-- In some areas served by [[Verizon]] in the northeast United States, it is still possible to red box local toll calls just outside of your [[Numbering plan area|NPA (area code)]], or while on the line with a live operator. -->