ExamPointers.com - Teletext

Last Updated: Wednesday, 8 June 2022 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 26 - Enhanced Display Facilities & VPT

Bytes in Packet 26 - Enhanced Display Facilities & VPT

1-2	3	4-5	6	7-9	10-12	13-15	16-18	19-21	22-24	25-27	28-30	31-33	34-36	37-39	40-42	43-45
CRI 10101010	Framing 11100100	Magazine & Row Address	Designation Code	Group 1	Group 2	Group 3	Group 4	Group 5	Group 6	Group 7	Group 8	Group 9	Group 10	Group 11	Group 12	Group 13

Packet 26 contains address, mode and data within 3 bytes. The first two bytes are hamming coded 16bits->11bits (Address 6 bits, Mode 5 bits, Hamming 5 bits) and the last parity protected byte contains associated data.

Byte 1

Byte 2

Byte 3

The functions available using data in packet 26s are:

Set full row and screen colours.
Set cursor position.
Define scrolling area.
Set foreground and background colours.
Overwrite with a character from a supplementary character set (additional symbols (figure 1), smooth mosaics and lines (figure 2). DRCS character etc.).
Additional flash controls (different flash rates, 3-phase flash which creates the impression of movement, inverted flash).
Set parallel attribute (double height/width/size, conceal etc.).
Set latching shift to a different character set.

Example Packet 26 Capture - 10 August 1997

        CARLTON 601 Thu 10 Apr 23:42:57
������  � ��   
• ��•��…� •� ���• 
��”• ••‚�������� ‹•���� PROGRAMMES ����
ŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒ THURSDAY ŒŒŒŒ
10.04.
22.00 News At Ten; Weather 
22.30 London Tonight 
22.40 Do I Not Like That! 
23.40 Alfred Hitchcock Presents 

00.40 Funny Business see 609
01.15 Ed's Night Party see 609
2.45 Club Nation see 609
02.40 Access All Areas see 609

03.05 Stand and Deliver see 609
04.05 Short Story Cinema see 609
04.35 Being There see 609
05.00 The Time...The Place 
05.30 ITN Morning News 
06.00 
ŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒŒ
Tomorrow Subtitles Films London Tonight

News Heads Sport Election Weather

Packet 26/0

	1	0	00000000	00000000	0

1	2	99	01100011	10010	18
	3	163	10100011	10001	17
	4	158	10011110	10011110	158

2	5	162	10100010	10000	16
	6	39	00100111	10011	19
	7	144	10010000	10010000	144

3	8	113	01110001	10000	16
	9	50	00110010	11001	25
	10	132	10000100	10000100	132

4	11	123	01111011	11010	26
	12	170	10101010	10101	21
	13	162	10100010	10100010	162

5	14	185	10111001	11010	26
	15	152	10011000	01100	12
	16	128	10000000	10000000	128

6	17	124	01111100	11110	30
	18	170	10101010	10101	21
	19	34	00100010	00100010	34

7	20	186	10111010	11010	26
	21	152	10011000	01100	12
	22	176	10110000	10110000	176

8	23	130	10000010	00010	2
	24	171	10101011	10101	21
	25	34	00100010	00100010	34

9	26	178	10110010	10000	16
	27	24	00011000	01100	12
	28	64	01000000	01000000	64

10	29	132	10000100	00100	4
	30	43	00101011	10101	21
	31	35	00100011	00100011	35

11	32	178	10110010	10000	16
	33	24	00011000	01100	12
	34	64	01000000	01000000	64

12	35	163	10100011	10010	18
	36	167	10100111	10011	19
	37	17	00010001	00010001	17

13	38	148	10010100	00110	6

Packet 26/1

	1	1	00000001	00000001	1

1	2	178	10110010	10000	16
	3	24	00011000	01100	12
	4	64	01000000	01000000	64

2	5	161	10100001	10000	16
	6	43	00101011	10101	21
	7	129	10000001	10000001	129

3	8	178	10110010	10000	16
	9	24	00011000	01100	12
	10	21	00010101	00010101	21

4	11	165	10100101	10100	20
	12	43	00101011	10101	21
	13	2	00000010	00000010	2

5	14	176	10110000	10000	16
	15	24	00011000	01100	12
	16	197	11000101	11000101	197

6	17	187	10111011	11000	24
	18	43	00101011	10101	21
	19	2	00000010	00000010	2

7	20	178	10110010	10000	16
	21	24	00011000	01100	12
	22	64	01000000	01000000	64

8	23	194	11000010	00010	2
	24	171	10101011	10101	21
	25	131	10000011	10000011	131

9	26	187	10111011	11010	26
	27	152	10011000	01100	12
	28	5	00000101	00000101	5

10	29	197	11000101	00100	4
	30	43	00101011	10101	21
	31	4	00000100	00000100	4

11	32	187	10111011	11010	26
	33	152	10011000	01100	12
	34	5	00000101	00000101	5

12	35	219	11011011	01000	8
	36	43	00101011	10101	21
	37	4	00000100	00000100	4

13	38	184	10111000	11010	26
	39	152	10011000	01100	12
	40	53	00110101	00110101	53

Packet 26/2

	1	2	00000010	00000010	2

1	2	221	11011101	01110	14
	3	171	10101011	10101	21
	4	7	00000111	00000111	7

2	5	185	10111001	11010	26
	6	152	10011000	01100	12
	7	128	10000000	10000000	128

3	8	233	11101001	11010	26
	9	171	10101011	10101	21
	10	133	10000101	10000101	133

4	11	186	10111010	11010	26
	12	152	10011000	01100	12
	13	176	10110000	10110000	176

5	14	110	01101110	11110	30
	15	175	10101111	10111	23
	16	6	00000110	00000110	6

6	17	185	10111001	11010	26
	18	152	10011000	01100	12
	19	128	10000000	10000000	128

7	20	116	01110100	10101	21
	21	127	01111111	11111	31
	22	255	11111111	11111111	255

8	23	116	01110100	10101	21
	24	127	01111111	11111	31
	25	255	11111111	11111111	255

9	26	116	01110100	10101	21
	27	127	01111111	11111	31
	28	255	11111111	11111111	255

10	29	116	01110100	10101	21
	30	127	01111111	11111	31
	31	255	11111111	11111111	255

11	32	116	01110100	10101	21
	33	127	01111111	11111	31
	34	255	11111111	11111111	255

12	35	116	01110100	10101	21
	36	127	01111111	11111	31
	37	255	11111111	11111111	255

13	38	116	01110100	10101	21
	39	127	01111111	11111	31
	40	255	11111111	11111111	255