Editing Red box (phreaking) (section)

==Technical details==

===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. -->

===Canada===
Canada formerly used a US-style ACTS coin phone system with a tone pair which would beep once for a nickel, twice for a dime and five times on receiving a quarter. These phones did not accept $1 coins (or the later $2 coin) and disappeared with the roll-out of [[Nortel payphones#Millennium|Nortel Millennium]] payphones in the 1990s. The Millennium sets do not use ACTS in-band signalling tones as all coin-handling is automated in the phone itself.

===United Kingdom===
In the [[United Kingdom|UK]], a 1000&nbsp;Hz tone for 200 ms represents a 10[[pence|p]] coin, and 1000&nbsp;Hz for 350 ms represents a 50p coin.  Prior to this system, the earliest UK pay-on-answer payphones used a resistance, inserted into the loop for one or several short periods followed by a short flash (complete disconnection), to signal units of money inserted.  Phreaks simulated these signals by unscrewing the microphone cover of the handset and inserting into the microphone circuit a resistor in parallel with a press-to-open push-button, getting the timing correct was difficult and failure to do this would result in the relay set controlling the call at the exchange to release, dropping the call.  This was hard to do inconspicuously in outdoor payphones, and was more common indoors (e.g., in student halls of residence). Manipulating a telephone in this way was illegal and carried the specific offence of "[[abstracting electricity]]" from the GPO (later the Post Office and later still [[BT Group|BT]].)