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  제목   해킹 강좌 #6 1998/06/30 (14:28)
이름 김효원
번호 37
조회 334
본문 DTMF 주파수란 무엇인가?


DTMF는 Dual Tone Multi Frequency의 약자이다. 이것은 전화의 숫자판에서 숫자를 누를 때 발생하는 음이다. 이 음은 행과 열의 합만큼이다. ABCD 키는 표준 전화기에는 없다.

1209 1336 1477 1633

697 1 2 3 A

770 4 5 6 B

852 7 8 9 C

941 * 0 # D





전화음의 주파수는 무엇인가?


Type Hz On Off

---------------------------------------------------------------------

Dial Tone 350 & 440 --- ---

Busy Signal 480 & 620 0.5 0.5

Toll Congestion 480 & 620 0.2 0.3

Ringback (Normal) 440 & 480 2.0 4.0

Ringback (PBX) 440 & 480 1.5 4.5

Reorder (Local) 480 & 620 3.0 2.0

Invalid Number 200 & 400

Hang Up Warning 1400 & 2060 0.1 0.1

Hang Up 2450 & 2600 --- ---





<* (LASS)코드는 모두 무엇인가?


Local Area Signal Service(LASS)와 Custom Calling Feature Control Code:


(이것들이 표준으로 생각되나, 지역적으로 차이가 있을 수 있다)

(These appear to be standard, but may be changed locally)

Service Tone Pulse/rotary Notes

--------------------------------------------------------------------------

Assistance/Police *12 n/a [1]

Cancel forwarding *30 n/a [C1]

Automatic Forwarding *31 n/a [C1]

Notify *32 n/a [C1] [2]

Intercom Ring 1 (..) *51 1151 [3]

Intercom Ring 2 (.._) *52 1152 [3]

Intercom Ring 3 (._.) *53 1153 [3]

Extension Hold *54 1154 [3]

Customer Originated Trace *57 1157

Selective Call Rejection *60 1160 (or Call Screen)

Selective Distinct Alert *61 1161

Selective Call Acceptance *62 1162

Selective Call Forwarding *63 1163

ICLID Activation *65 1165

Call Return (outgoing) *66 1166

Number Display Blocking *67 1167 [4]

Computer Access Restriction *68 1168

Call Return (incoming) *69 1169

Call Waiting disable *70 1170 [4]

No Answer Call Transfer *71 1171

Usage Sensitive 3 way call *71 1171

Call Forwarding: start *72 or 72# 1172

Call Forwarding: cancel *73 or 73# 1173

Speed Calling (8 numbers) *74 or 74# 1174

Speed Calling (30 numbers) *75 or 75# 1175

Anonymous Call Rejection *77 1177 [5] [M: *58]

Call Screen Disable *80 1180 (or Call Screen) [M: *50]

Selective Distinct Disable *81 1181 [M: *51]

Select. Acceptance Disable *82 1182 [4] [7]

Select. Forwarding Disable *83 1183 [M: *53]

ICLID Disable *85 1185

Call Return (cancel out) *86 1186 [6] [M: *56]

Anon. Call Reject (cancel) *87 1187 [5] [M: *68]

Call Return (cancel in) *89 1189 [6] [M: *59]

Notes:

[C1] - Means code used for Cellular One service

[1] - for cellular in Pittsburgh, PA A/C 412 in some areas

[2] - indicates that you are not local and maybe how to reach you

[3] - found in Pac Bell territory; Intercom ring causes a distinctive

ring to be generated on the current line; Hold keeps a call

connected until another extension is picked up

[4] - applied once before each call

[5] - A.C.R. blocks calls from those who blocked Caller ID

(used in C&P territory, for instance)

[6] - cancels further return attempts

[7] - *82 (1182) has been mandated to be the nationwide code for

"Send CLID info regardless of the default setting on this

phone line."

[M: *xx] - alternate code used for MLVP (multi-line variety package)

by Bellcore. It goes by different names in different RBOCs.

In Bellsouth it is called Prestige. It is an arrangement of

ESSEX like features for single or small multiple line groups.

The reason for different codes for some features in MLVP is that

call-pickup is *8 in MLVP so all *8x codes are reassigned *5x





무선 전화가 작동하는 주파수는 무엇인가?


1 세대 46/49Mhz 전화의 주파수가 아래에 있다.

Channel Handset Transmit Base Transmit

------- ---------------- -------------

1 49.670mhz 46.610mhz

2 49.845 46.630

3 49.860 46.670

4 49.770 46.710

5 49.875 46.730

6 49.830 46.770

7 49.890 46.830

8 49.930 46.870

9 49.990 46.930

10 49.970 46.970


"900Mhz"의 신세대 무선전화기는 902-228Mhz 사이의 주파수가 할당된다. 30-100Khz의 채널당 여유가 있다.


----------------------------------------------------------------

Panasonic KX-T9000 (60 Channels)

base 902.100 - 903.870 Base frequencies (30Khz spacing)

handset 926.100 - 927.870 Handset frequencies

CH BASE HANDSET CH BASE HANDSET CH BASE HANDSET

-- ------- ------- -- ------- ------- -- ------- -------

01 902.100 926.100 11 902.400 926.400 21 902.700 926.700

02 902.130 926.130 12 902.430 926.430 22 902.730 926.730

03 902.160 926.160 13 902.460 926.460 23 902.760 926.760

04 902.190 926.190 14 902.490 926.490 24 902.790 926.790

05 902.220 926.220 15 902.520 926.520 25 902.820 926.820

06 902.250 926.250 16 902.550 926.550 26 902.850 926.850

07 902.280 926.280 17 902.580 926.580 27 902.880 926.880

08 902.310 926.310 18 902.610 926.610 28 902.910 926.910

09 902.340 926.340 19 902.640 926.640 29 902.940 926.940

10 902.370 926.370 20 902.670 926.670 30 902.970 926.970

31 903.000 927.000 41 903.300 927.300 51 903.600 927.600

32 903.030 927.030 42 903.330 927.330 52 903.630 927.630

33 903.060 927.060 43 903.360 927.360 53 903.660 927.660

34 903.090 927.090 44 903.390 927.390 54 903.690 927.690

35 903.120 927.120 45 903.420 927.420 55 903.720 927.720

36 903.150 927.150 46 903.450 927.450 56 903.750 927.750

37 903.180 927.180 47 903.480 927.480 57 903.780 927.780

38 903.210 927.210 48 903.510 927.510 58 903.810 927.810

39 903.240 927.240 49 903.540 927.540 59 903.840 927.840

40 903.270 927.270 50 903.570 927.570 60 903.870 927.870

------------------------------------------------------------

V-TECH TROPEZ DX900 (20 CHANNELS)

905.6 - 907.5 TRANSPONDER (BASE) FREQUENCIES (100 KHZ SPACING)

925.5 - 927.4 HANDSET FREQUENCIES

CH BASE HANDSET CH BASE HANDSET CH BASE HANDSET

-- ------- ------- -- ------- ------- -- ------- -------

01 905.600 925.500 08 906.300 926.200 15 907.000 926.900

02 905.700 925.600 09 906.400 926.300 16 907.100 927.000

03 905.800 925.700 10 906.500 926.400 17 907.200 927.100

04 905.900 925.800 11 906.600 926.500 18 907.300 927.200

05 906.000 925.900 12 906.700 926.600 19 907.400 927.300

06 906.100 926.000 13 906.800 926.700 20 907.500 927.400

07 906.200 926.100 14 906.900 926.800

------------------------------------------------------------

Other 900mhz cordless phones

AT&T #9120 - - - - - 902.0 - 905.0 & 925.0 - 928.0 MHZ

OTRON CORP. #CP-1000 902.1 - 903.9 & 926.1 - 927.9 MHZ

SAMSUNG #SP-R912- - - 903.0 & 927.0 MHZ

------------------------------------------------------------




발신자 식별자(caller-ID)는 무엇인가?

This FAQ answer is stolen from Rockwell:

Calling Number Delivery (CND), better known as Caller ID, is a

telephone service intended for residential and small business

customers. It allows the called Customer Premises Equipment (CPE) to

receive a calling party's directory number and the date and time of

the call during the first 4 second silent interval in the ringing

cycle.

Parameters

~~~~~~~~~~

The data signalling interface has the following characteristics:

Link Type: 2-wire, simplex

Transmission Scheme: Analog, phase-coherent FSK

Logical 1 (mark) 1200 +/- 12 Hz

Logical 0 (space) 2200 +/- 22 Hz

Transmission Rate: 1200 bps

Transmission Level: 13.5 +/- dBm into 900 ohm load


Protocol

~~~~~~~~

The protocol uses 8-bit data words (bytes), each bounded by a start

bit and a stop bit. The CND message uses the Single Data Message

format shown below.

| Channel | Carrier | Message | Message | Data | Checksum |

| Seizure | Signal | Type | Length | Word(s) | Word |

| Signal | | Word | Word | | |

Channel Seizure Signal

~~~~~~~~~~~~~~~~~~~~~~

The channel seizure is 30 continuous bytes of 55h (01010101) providing

a detectable alternating function to the CPE (i.e. the modem data

pump).

Carrier Signal

~~~~~~~~~~~~~~

The carrier signal consists of 130 +/- 25 mS of mark (1200 Hz) to

condition the receiver for data.

Message Type Word

~~~~~~~~~~~~~~~~~

The message type word indicates the service and capability associated

with the data message. The message type word for CND is 04h

(00000100).

Message Length Word

~~~~~~~~~~~~~~~~~~~

The message length word specifies the total number of data words to

follow.

Data Words

~~~~~~~~~~

The data words are encoded in ASCII and represent the following

information:

o The first two words represent the month

o The next two words represent the day of the month

o The next two words represent the hour in local military time

o The next two words represent the minute after the hour

o The calling party's directory number is represented by the

remaining words in the data word field

If the calling party's directory number is not available to the

terminating central office, the data word field contains an ASCII "O".

If the calling party invokes the privacy capability, the data word

field contains an ASCII "P".

Checksum Word

~~~~~~~~~~~~~

The Checksum Word contains the twos complement of the modulo 256 sum

of the other words in the data message (i.e., message type, message

length, and data words). The receiving equipment may calculate the

modulo 256 sum of the received words and add this sum to the received

checksum word. A result of zero generally indicates that the message

was correctly received. Message retransmission is not supported.

Example CNS Single Data Message

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

An example of a received CND message, beginning with the message type

word, follows:

04 12 30 39 33 30 31 32 32 34 36 30 39 35 35 35 31 32 31 32 51

04h= Calling number delivery information code (message type word)

12h= 18 decimal; Number of data words (date,time, and directory

number words)

ASCII 30,39= 09; September

ASCII 33,30= 30; 30th day

ASCII 31,32= 12; 12:00 PM

ASCII 32,34= 24; 24 minutes (i.e., 12:24 PM)

ASCII 36,30,39,35,35,35,31,32,31,32= (609) 555-1212; calling

party's directory number

51h= Checksum Word

Data Access Arrangement (DAA) Requirements

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

To receive CND information, the modem monitors the phone line between

the first and second ring bursts without causing the DAA to go off

hook in the conventional sense, which would inhibit the transmission

of CND by the local central office. A simple modification to an

existing DAA circuit easily accomplishes the task.

Modem Requirements

~~~~~~~~~~~~~~~~~~

Although the data signalling interface parameters match those of a

Bell 202 modem, the receiving CPE need not be a Bell 202 modem. A

V.23 1200 bps modem receiver may be used to demodulate the Bell 202

signal. The ring indicate bit (RI) may be used on a modem to indicate

when to monitor the phone line for CND information. After the RI bit

sets, indicating the first ring burst, the host waits for the RI bit

to reset. The host then configures the modem to monitor the phone

line for CND information.

Signalling

~~~~~~~~~~

According to Bellcore specifications, CND signalling starts as early

as 300 mS after the first ring burst and ends at least 475 mS before

the second ring burst

Applications

~~~~~~~~~~~~

Once CND information is received the user may process the information

in a number of ways.

1. The date, time, and calling party's directory number can be

displayed.

2. Using a look-up table, the calling party's directory number can be

correlated with his or her name and the name displayed.

3. CND information can also be used in additional ways such as for:

a. Bulletin board applications

b. Black-listing applications

c. Keeping logs of system user calls, or

d. Implementing a telemarketing data base

References

~~~~~~~~~~

For more information on Calling Number Delivery (CND), refer to

Bellcore publications TR-TSY-000030 and TR-TSY-000031.

To obtain Bellcore documents contact:

Bellcore Customer Service

60 New England Avenue, Room 1B252

Piscataway, NJ 08834-4196

(908) 699-5800




발신자 식별자는 어떻게 막을 수 있나?

Always test as much as possible before relying on any method of blocking

Caller-ID. Some of these methods work in some areas, but not in others.

Dial *67 before you dial the number. (141 in the United Kingdom)

Dial your local TelCo and have them add Caller-ID block to your line.

Dial the 0 Operator and have him or her place the call for you.

Dial the call using a pre-paid phone card.

Dial through Security Consultants at (900)PREVENT for U.S. calls

($1.99/minute) or (900)STONEWALL for international calls ($3.99/minute).

Dial from a pay phone. :-)



PBX 란 무엇인가?

PBX는 Private Branch Exchange(구내 교환기)의 약어이다. PBX는 소형 전화 교환기로 회사가 기관이 소유한다. 천명의 피고용인이 있는 회사를 가정하자. PBX가 없을 경우, 1000개의 전화선이 필요하다. 그렇지만, 10%정도의 사람만이 동시에 전화를 사용한다고 하자. 피고용인이 전화를 할려고 할 때, 이용가능한 외선을 찾아서 연결하는 컴퓨터가 있다면 어떨까? 이런 종류의 시스템이 있다면 전화선 비용의 10분의 1만 부담하면 된다.


VMB란 무엇인가?

VMB는 Voicie Mail Box(음성 메일 박스)의 약자이다. VMB는 수십만의 사용자에 서비스를 하는 자동 응답기이다. 각 사용자는 자신의 음성 메일 박스를 이 시스템 내에 가지게 된다. 각 메일 박스는 박스 번호와 암호(passcode)를 가지게 된다.


암호가 없이 VMB 시스템에 음성 메시지를 남길 수 있다. 암호가 있으면, 메일박스를 정리하고 메시지를 읽을 수 있다. 때때로, 디폴트로 생성된 메일박스나 더 이상 사용되지 않는 메일박스가 있을 수 있다. 이러한 메일박스를 암호를 추측하여 탈취할 수 있다. 대개 암호는 1234와 같이 흔한 것이다.


ABCD 음은 무엇을 위한 것인가?


ABCD 음(tone)은 DTFM 음에 추가한 것이다. ABCD 음은 미국 군사 전화 망(AutoVon)에서 이용되고, Automatic Call Distributor(ACD)에서 이용되고, PBX의 제어 메시지로, 아마추어 무선의 자동패치(auto-patch)에서 사용된다.

The ABCD tones are simply additional DTFM tones that may be used in any

way the standard (0-9) tones are used. The ABCD tones are used in the

U.S. military telephone network (AutoVon), in some Automatic Call

Distributor (ACD) systems, for control messages in some PBX systems, and

in some amateur radio auto-patches.

In the AutoVon network, special telephones are equipped with ABCD keys.

The ABCD keys are defined as such:

A - Flash

B - Flash override priority

C - Priority communication

D - Priority override

Using a built-in maintenance mode of the Automatic Call Distributor

(ACD) systems once used by Directory Assistance operators, you could

connect two callers together.

The purpose of the Silver Box is to create the ABCD tones.

See also "What are the DTMF Frequencies?"


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