Direct Access Test Unit
Encyclopedia
Direct Access Test Units (DATUs) are special PSTN phone numbers that terminate at the central office switch
in a telephone company's local exchange that provide switchmen and telco technicians with a circuit for testing lines in various ways.
Among the many things a DATU can do are:
DATU's are primarily non-published numbers, though they usually have the phone number XXX-9935 (where XXX represents the local exchange). They are password protected for security, though many telcos leave the default password
of 1111 set.
In July of 2004, New York
phone phreak William Quinn, also known as "decoder", was arrested and charged with accessing Verizon's DATU numbers on over 100 occasions. Verizon subsequently claimed in press releases that it spent $120,000 to change the passwords on all the DATU numbers (it is unclear if this represented Verizon changing the DATU passwords from the default and if so why this had not been done at time of initial installation).
Switch
In electronics, a switch is an electrical component that can break an electrical circuit, interrupting the current or diverting it from one conductor to another....
in a telephone company's local exchange that provide switchmen and telco technicians with a circuit for testing lines in various ways.
Among the many things a DATU can do are:
- Make certain electrical connections, such as shorting a line's tip to ring, tip to ground, or ring to ground.
- Play certain tones on the line (high tone, low tone) to test the line's audio circuit.
- Monitor the audio circuit on the line if it is in use (though this only provides a scrambled rendition of the line's audio circuit for privacy and security reasons).
- Create and modify certain variables such as counters and timers on the CO switch, as well as adding and modifying exchanges.
- Remove a line from permanent signalPermanent signalPermanent Signal in US telephony jargon, or Permanent Loop in British usage, is a condition in which a POTS line is off-hook without connection for an extended period of time. This is indicated in modern switches by the silent termination after the off hook tone times out and the telephone...
holding state.
DATU's are primarily non-published numbers, though they usually have the phone number XXX-9935 (where XXX represents the local exchange). They are password protected for security, though many telcos leave the default password
Default password
Where a device needs a username and/or password to login, a default password is usually provided that allows the device to be accessed during its initial setup...
of 1111 set.
In July of 2004, New York
New York
New York is a state in the Northeastern region of the United States. It is the nation's third most populous state. New York is bordered by New Jersey and Pennsylvania to the south, and by Connecticut, Massachusetts and Vermont to the east...
phone phreak William Quinn, also known as "decoder", was arrested and charged with accessing Verizon's DATU numbers on over 100 occasions. Verizon subsequently claimed in press releases that it spent $120,000 to change the passwords on all the DATU numbers (it is unclear if this represented Verizon changing the DATU passwords from the default and if so why this had not been done at time of initial installation).