Encyclopedia of Telecommunications

Reference data on units and symbols used in telecommunications.

Units

Frequency spectrum

Greek alphabet and typical meanings

Transmission rates

Decimal/Binary/Hexadecimal/Octal/Baudot/ASCII

UNITS

The International System of Units

The International system of Units (SI) comprises seven basic units which are assumed to be independent of each other:

Derived quantities are defined in terms of the severn base quantities of which the following are examples:

Other derived units have been given special names of which the following are examples:

Other derived quantities make use of SI units with special names, for example:

There are other units outside the International System of Units (SI) that are widely used and accepted for use within the SI.

Prefixes are used with SI units for multiples and sub-multiples as shown below. The only exception applies to the basic SI unit for mass (kilogram) which already uses a prefix and hence all prefixes apply to the gram.

Special prefixes for binary multiples were approved by the International Electrotechnical Commisiion in 1998 but are not part of the International System of Units. They are:

END of SI UNits

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

For Bit/Byte/Baud see main entries

Typical IP port numbers

File format suffixes

Electromagnetic frequency spectrum

Formulae for simple R, L, C networks (RDFRE - p134)

Greek alphabet

Morse code

Telegraph codes - See Baudot code in tables below.

There are four sub-atomic particles of particular interest to the telecommunications engineer (others, for example, neutrino, positron, meson are of less interest) - these are:

The electron
The proton
The neutron
The photon

Shannon - check Millennium edition

Transmission rates

See also bits and bytes.

North American Digital Hierarchy

DS-0, 1 X 64kbit/s channels 64 kbit/s line rate
DS-1, 24 X 64kbit/s channels, 1.54 Mbit/s
DS-2, 96 ....., 6.31 Mbit/s
DS-3, 672....., 44.74 Mbit/s
DS-4 2,016..., 139.26 Mbit/s

T1: 1.544 Mbit/s (also DS-1)
T2: 6.312 Mbit/s
T3: 44.736 Mbit/s (also DS-2)

European hierarchy

E1: 2.048 Mbit/s
E2: 8.848 Mbit/s
E3: 34.304 Mbit/s
E4: 139.264 Mbit/s

SONET line rates

STS-1 51.84 Mbit/s (building block of SONET)
STS-3; OC-3; STM-1: 155.52 Mbit/s
STS-12; OC-12; STM-4: 622.08 Mbit/s
STS-24; OC-24;1.24 Gbit/s
STS-48; OC-48; STM-16: 2488.32 Mbit/s (a.k.a. 2.5 Gbit/s)
STS-192; OC192; 9.95 Gbit/s

OC192: 10 Gbit/s
OC768: 40 Gbit/s

Check all original standards bodies documents.

Esp ITU usual series G, H, X, V etc

ASCII chart

Notes about origin, characters, words, bytes, bits.

Note: the calculator function in the widely available Microsoft Windows operating system can be used to convert numbers between decimal, binary, octal and hexadecimal.

Decimal	Binary	Baudot letter	Baudot figure	Octal	Hexadecimal	ASCII Character
0	0	Unused	Unused	0	0
1	1	T	5	1	1
2	10	CR	CR	2	2
3	11	O	9	3	3
4	100	Space	Space	4	4
5	101	H	'	5	5
6	110	N	,	6	6
7	111	M	.	7	7
8	1000	Line feed	Line feed	10	8
9	1001	L	)	11	9
10	1010	R	4	12	A
11	1011	G	&	13	B
12	1100	I	8	14	C
13	1101	P	0	15	D
14	1110	C	:	16	E
15	1111	V	;	17	F
16	10000	E	3	20	10
17	10001	Z	"	21	11
18	10010	D	$	22	12
19	10011	B	?	23	13
20	10100	S	Bell	24	14
21	10101	Y	6	25	15
22	10110	F	!	26	16
23	10111	X	/	27	17
24	11000	A	-	30	18
25	11001	W	2	31	19
26	11010	J	'	32	1A
27	11011	Figures		33	1B
28	11100	U	7	34	1C
29	11101	Q	Q	35	1D
30	11110	K	(	36	1E
31	11111	Letters		37	1F
32	100000			40	20
33				41	21
34				42	22
35				43	23
36				44	24
37				45	25
38				46	26
39				47	27
40	101000			50	28
41				51	29
42				52	2A
43				53	2B
44				54	2C
45				55	2D
46				56	2E
47				57	2F
48	110000			60	30
49				61	31
50				62	32
51				63	33
52				64	34
53				65	35
54				66	36
55	110111			67	37
56				70	38
57				71	39
58				72	3A
59				73	3B
60				74	3C
61				75	£d
62				76	3E
63	111111			77	3F

Decimal	Binary	Octal	Hexadecimal	ASCII Character
64	1000000	100	40
65		101	41
66		102	42
67		103	43
68		104	44
69		105	45
70	1000110	106	46
71		107	47
72		110	48
73		111	49
74		112	4A
75		113	4B
76		114	4C
77		115	4D
78		116	4E
79		117	4F
80	1010000	120	50
81		121	51
82		122	52
83		123	53
84		124	54
85		125	55
86		126	56
87		127	57
88		130	58
89		131	59
90	1011010	132	5A
91		133	5B
92		134	5C
93		135	5D
94		136	5E
95		137	5F
96		140	60
97		141	61
98		142	62
99		143	63
100	1100100	144	64
101		145	65
102		146	66
103		147	67
104		150	68
105		151	69
106		152	6A
107		153	6B
108		154	6C
109		155	6D
110	1101110	156	6E
111		157	6F
112		160	70
113		161	71
114		162	72
115		163	73
116		164	74
117		165	75
118		166	76
119		167	77
120		170	78
121		171	79
122		172	7A
123		173	7B
124		174	7C
125		175	7D
126		176	7E
127	1111111	177	7F

Decimal	Binary	Octal	Hexadecimal	ASCII Character
128	10000000	200	80
129		201	81
130		202	82
131		203	83
132		204	84
133		205	85
134		206	86
135		207	87
136		210	88
137		211	89
138		212	8A
139		213	8B
140		214	8C
141		215	8D
142		216	8E
143		217	8F
144		220	90
145		221	91
146		222	92
147		223	93
148		224	94
149		225	95
150	10010110	226	96
151		227	97
152		230	98
153		231	99
154		232	9A
155		233	9B
156		234	9C
157		235	9D
158		236	9E
159		237	9F
160	10100000	240	A0
161			A1
162			A2
163			A3
164			A4
165			A5
166			A6
167			A7
168			A8
169			A9
170	10101010	252	AA
171
172
173
174
175
176
177
178
179
180	10110100	264	B4
181
182
183
184
185
186
187
188
189
190
191	10111111	277	BF

Decimal	Binary	Octal	Hexadecimal	ASCII Character
192		100	40
193		101	41
194		102	42
195		103	43
196		104	44
197		105	45
198		106	46
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255	11111111	377	FF