ExamPointers.com - Teletext

Last Updated: Friday, 27 February 2009 By: Steve Warner


	Teletext Information
	Teletext Transmission
	Hamming Codes
	Packet 24 & 27
	Packet 26
	Packet 30
	Packet 31
	Datacast
	Captured
	I2C
	I2C Tuner
	WinTV
	Semiconductors
	Other Sites

Packet 30 - Broadcasting Services Data Packet & PDC

It contains a 20 byte string that has the channels name stored within it, this how every is transmitted using 8 bits so to display the text properly it is necessary to and the received value with 127.

BDSP 8/30 Format 1

Byte No.

Bit No.

Weight

Sign

2^-2

2^-1

2⁰

2¹

2²

2³

0
1

MJD Digit
Weight 10⁴

MJD Digit
Weight 10²

MJD Digit
Weight 10³

MJD Digit
Weight 10⁰

MJD Digit
Weight 10¹

UTC Hours
Units

UTC Hours
Tens

UTC Minutes
Units

UTC Minutes
Tens

UTC Seconds
Units

UTC Seconds
Tens

BDSP 8/30 Format 2

13	0	LCI	1	Label Channel Identifier
	1	LCI	2
	2	LUF	1	Label Update Flag
	3	RES

14	0	PCS	1	Sound Status	20	0	PIL	15	Minute
	1	PCS	2			1	PIL	16
	2	RES	3			2	PIL	17
	3	RES	4			3	PIL	18
					21	0	PIL	19
15	0	CNI	1	Country		1	PIL	20
	1	CNI	2
	2	CNI	3			2	CNI	5	Country
	3	CNI	4			3	CNI	6
					22	0	CNI	7
16	0	CNI	9	Network		1	CNI	8
	1	CNI	10
						2	CNI	11	Network
	2	PIL	1	Day		3	CNI	12
	3	PIL	2		23	0	CNI	13
17	0	PIL	3			1	CNI	14
	1	PIL	4			2	CNI	15
	2	PIL	5			3	CNI	16

	3	PIL	6	Month	24	0	PTY	1	Program Type
18	0	PIL	7			1	PTY	2
	1	PIL	8			2	PTY	3
	2	PIL	9			3	PTY	4
					25	0	PTY	5
	3	PIL	10	Hour		1	PTY	6
19	0	PIL	11			2	PTY	7
	1	PIL	12			3	PTY	8
	2	PIL	13
	3	PIL	14

Dedicated VPS line

PCS

1	2	3	4
0	1	2	3

CNI

1	2	3	4
4	5	6	7

CNI

9	10
0	1

PIL

1	2	3	4	5	6
2	3	4	5	6	7

PIL

7	8	9	10	11	12	13	14
0	1	2	3	4	5	6	7

PIL

15	16	17	18	19	20
0	1	2	3	4	5

CNI

5	6
6	7

CNI

7	8	11	12	13	14	15	16
0	1	2	3	4	5	6	7

PTY

1	2	3	4	5	6	7	8
0	1	2	3	4	5	6	7

VPS

Day
binary

Month
binary

Hour
binary

Minute
binary

Country
binary

Network
binary

Program type
binary

TCC

INC

COC

UVPS

NPT

N	N	N	N
N	N	N	N
N	N	N	N
N	N	N	N
1	1	1	1
N	N	N	N

N	N
N	N
N	N
N	N
N	N
N	N

0	0	0	0	0	0
0	0	0	0	0	0
0	0	0	0	0	0
0	0	0	0	0	0
P	P	P	P	P	P
P	P	P	P	P	P

1	1	1	1
1	1	1	1
1	1	1	1
1	1	1	1
P	P	P	P
P	P	P	P

1	1	1	1	1
1	1	1	1	1
1	1	1	1	1
1	1	1	1	1
P	P	P	P	P
P	P	P	P	P

1	1	1	1	1	1
1	1	1	1	1	1
1	1	1	1	1	1
1	1	1	1	1	1
P	P	P	P	P	P
P	P	P	P	P	P

N	N	N	N
N	N	N	N
N	N	N	N
N	N	N	N
N	N	N	N
N	N	N	N

N	N	N	N	N	N
N	N	N	N	N	N
N	N	N	N	N	N
N	N	N	N	N	N
N	N	N	N	N	N
N	N	N	N	N	N

A	A	A	A	A	A	A	A
A	A	A	A	A	A	A	A
A	A	A	A	A	A	A	A
A	A	A	A	A	A	A	A
A	A	A	A	A	A	A	A
1	1	1	1	1	1	1	1

Bits 0 & 1 are used to specify the type of transmission sound

00 Unknown
01 Mono
10 Stereo
11 Dual

Example Packet 30 Capture - 10 August 1997

BBC1 100 48 - 11:35
 0 21 21 234 234 234 94 95 246 4 6 22 89 51 67 51 84 229 115 244 32 194 194 67 49 32 67 69 69 70 193 88 32 32 32 32 32 32 32 32
 0 0 0 15 15 15 3 3 13 0 1 1 2 5 1 5 0 12 5 12 4 9 9 1 4 4 1 0 0 1 8 2 4 4 4 4 4 4 4 4
 55êêê^_ö$&6Y3C3Tåsô@ÂÂC1@CEEFÁX@@@@@@@@
 55jjj^_v$&6Y3C3Test@BBC1@CEEFAX@@@@@@@@

BB2 100 48 - 11:35
 0 21 21 234 234 233 94 69 127 4 6 22 89 51 58 89 84 237 115 244 32 194 194 67 50 32 67 69 69 78 193 88 32 32 32 32 32 32 32 32
 0 0 0 15 15 14 3 0 7 0 1 1 2 5 7 2 0 14 5 12 4 9 9 1 5 4 1 0 0 3 8 2 4 4 4 4 4 4 4 4
 55êêé^E&127;$&6Y3:YTísô@ÂÂC2@CEENÁX@@@@@@@@
 55jji^E&127;$&6Y3:YTmst@BBC2@CEENAX@@@@@@@@

Carlton 100 48 - 11:09
 0 21 21 234 234 234 94 19 123 133 6 22 89 51 25 55 193 84 79 205 67 193 82 76 84 79 206 32 84 69 76 69 214 73 211 73 79 206 32 32
 0 0 0 15 15 15 3 1 7 8 1 1 2 5 2 5 8 0 3 10 1 8 1 2 0 3 11 4 0 0 2 0 9 2 9 2 3 11 4 4
 55êêê^3{…&6Y397ÁTOÍCÁRLTOÎ@TELEÖIÓIOÎ@@
 55jjj^3{&6Y397ATOMCARLTON@TELEVISION@@

Meridian 100 48 - 11:09
 0 21 21 234 234 202 94 19 123 133 6 22 89 51 68 38 193 84 79 205 205 229 242 233 100 233 97 110 32 194 242 239 97 100 227 97 115 244 32 32
 0 0 0 15 15 11 3 1 7 8 1 1 2 5 0 5 8 0 3 10 10 12 13 14 4 14 4 7 4 9 13 15 4 4 13 4 5 12 4 4
 55êêÊ^3{…&6Y3D&ÁTOÍÍåòédéan@Âòïadãasô@@
 55jjJ^3{&6Y3D&ATOMMeridian@Broadcast@@

Channel 4 100 48 - 11:30
 0 21 21 234 234 234 94 63 139 129 6 22 89 52 56 54 100 21 21 21 67 104 97 110 110 229 236 32 52 32 84 229 236 229 118 233 115 233 239 110
 0 0 0 15 15 15 3 7 11 8 1 1 2 4 6 5 4 0 0 0 1 6 4 7 7 12 14 4 4 4 0 12 14 12 5 14 5 14 15 7
 55êêê^?‹&6Y486d555Channåì@4@Tåìåvéséïn
 55jjj^?&6Y486d555Channel@4@Television