Examples of Communication Systems/General Description of ISDN - Revision history

Guenter at 17:00, 18 January 2025

2025-01-18T17:00:04Z

Guenter at 18:31, 16 January 2025

2025-01-16T18:31:06Z

Guenter at 16:31, 16 November 2022

2022-11-16T16:31:14Z

Guenter at 10:19, 10 November 2022

2022-11-10T10:19:20Z

Hwang at 09:30, 2 November 2022

2022-11-02T09:30:26Z

Hwang at 20:00, 1 November 2022

2022-11-01T20:00:50Z

Hwang at 19:44, 1 November 2022

2022-11-01T19:44:41Z

Hwang at 19:44, 1 November 2022

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Hwang at 19:41, 1 November 2022

2022-11-01T19:41:36Z

Hwang at 19:40, 1 November 2022

2022-11-01T19:40:39Z

@@ Line 29: / Line 29: @@
 {{BlaueBox|TEXT=
-$\text{ At the time of the English translation of this book&nbsp; $\rm (2022)$,&nbsp; it must not be concealed:}$&nbsp;
+$\text{ At the time of the English translation of this book&nbsp; $\rm (2022)$,&nbsp; the following facts must not be concealed:}$&nbsp;
 ISDN will no longer have a great future in Germany either.  In other countries it never had such great importance.
@@ Line 47: / Line 47: @@
 ==Goals and features of ISDN ==
 <br>
-The&nbsp; $\rm ISDN$&nbsp; ("Integrated Services Digital Network")&nbsp; standard,&nbsp; established since the late 1980s,&nbsp; is a service&ndash;integrated digital communications network with the aim,
+The&nbsp; $\rm ISDN$&nbsp; $($<i>Integrated Services Digital Network </i>$)$&nbsp; standard,&nbsp; established since the late 1980s,&nbsp; is a service&ndash;integrated digital communications network with the aim,
 # &nbsp; to digitize the analog signal transmission over telephone lines that had been common until then,&nbsp; thereby achieving better voice quality,
 # &nbsp; to continue using the network infrastructure available for analog signal transmission &ndash; in particular the copper cables laid at great expense over many years,

@@ Line 8: / Line 8: @@
 == # OVERVIEW OF THE FIRST MAIN CHAPTER # ==
 <br>
-$\rm I$ntegrated $\rm S$ervices $\rm D$igital $\rm N$etwork &nbsp; $\rm  (ISDN)$&nbsp; was the first unified digital network for voice,&nbsp; text,&nbsp; data,&nbsp; images,&nbsp; video and multimedia communications.&nbsp; It was introduced in the late 1980s and and had about 25 million users in Germany in 2004, for example.
+$\rm I$ntegrated $\rm S$ervices $\rm D$igital $\rm N$etwork &nbsp; $\rm  (ISDN)$&nbsp; was the first unified digital network for voice,&nbsp; text,&nbsp; data,&nbsp; images,&nbsp; video and multimedia communications.&nbsp; It was introduced in the late 1980s and had about 25 million users in Germany in 2004, for example.
-Compared with the analog telecommunications methods that were common before,&nbsp; ISDN has
+Compared with the analog telecommunications methods that were common before,&nbsp; ISDN has offered
-*offered many new or enhanced services,
+* many new or enhanced services,
 *faster transmission,
-*better voice quality,&nbsp; and
+*better voice quality.
@@ Line 30: / Line 28: @@
-At the time of the English translation of this book&nbsp; $\rm (2022)$,&nbsp; however,&nbsp; it must not be concealed:
+{{BlaueBox|TEXT=
-* ISDN will no longer have a great future in Germany either - in other countries it never had such great importance.
+$\text{ At the time of the English translation of this book&nbsp; $\rm (2022)$,&nbsp; it must not be concealed:}$&nbsp;
-* The German provider &nbsp; &raquo;Deutsche Telekom&laquo;&nbsp; had long announced that it would switch off ISDN in 2018 and replace it with its&nbsp; "Next Generation Network"&nbsp; $\rm (NGN)$&nbsp; with packet-switched network infrastructure.
+ISDN will no longer have a great future in Germany either.  In other countries it never had such great importance.
-*Vodafone will follow this example by 2022 at the latest.
+*We have nevertheless decided to continue this chapter&nbsp; $($which was highly topical in the early 2000s$)$&nbsp; in the&nbsp; $\rm LNTwww$,&nbsp; however,&nbsp; clearly shortened. &nbsp;

@@ Line 121: / Line 121: @@
 *the subscribers,&nbsp; as the network branches out to the maximum in this area.
-[[File:EN_LZI_T_4_3_S2.png| right|frame|Structure of the local loop area '''KORREKTUR: Fiber''']]
+[[File:EN_LZI_T_4_3_S2_neu.png| right|frame|Structure of the local loop area]]
 [[File:EN_LZI_T_4_3_S1b.png|right|frame| Bundling and twisting of copper wires]]

@@ Line 10: / Line 10: @@
 $\rm I$ntegrated $\rm S$ervices $\rm D$igital $\rm N$etwork &nbsp; $\rm  (ISDN)$&nbsp; was the first unified digital network for voice,&nbsp; text,&nbsp; data,&nbsp; images,&nbsp; video and multimedia communications.&nbsp; It was introduced in the late 1980s and and had about 25 million users in Germany in 2004, for example.
-Compared with the analog telecommunications processes '''KORREKTUR: methods?''' that were common before, ISDN has
+Compared with the analog telecommunications methods that were common before,&nbsp; ISDN has
 *offered many new or enhanced services,

@@ Line 261: / Line 261: @@
 *By using large values of&nbsp; $M$&nbsp; or&nbsp; $N$,&nbsp; one can increase the PCM quality at the expense of the effort,&nbsp; the transmission rate,&nbsp; and the high-fruquency bandwidth thus required. For ISDN,&nbsp; a good compromise&nbsp; $($for the 1990s$)$&nbsp; between desirable quality and required bit rate was standardized with&nbsp; $N = 8$ &nbsp;  ⇒  &nbsp; $M = 256$.&nbsp;
-*The ISDN bit rate&nbsp; $($for each of the two beerer channels$)$&nbsp; is&nbsp; $8 · 8000 \ \rm 1/s = 64 \ kbit/s$&nbsp; according to the above specifications.&nbsp; The quantization SNR is thus
+*The ISDN bit rate&nbsp; $($for each of the two bearer channels$)$&nbsp; is&nbsp; $8 · 8000 \ \rm 1/s = 64 \ kbit/s$&nbsp; according to the above specifications.&nbsp; The quantization SNR is thus
 :$$\rho_{\rm Q} = 2^{16}\hspace{0.3cm}\Rightarrow \hspace{0.3cm}

@@ Line 181: / Line 181: @@
 ==Four-wire and two-wire transmission==
 <br>
-A communication link usually operates – as is the case with ISDN – in&nbsp; '''full duplex mode''',&nbsp i.e. the two communication partners transmit continuously and independently of each other.
+A communication link usually operates – as is the case with ISDN – in&nbsp; '''full duplex mode''',&nbsp; i.e. the two communication partners transmit continuously and independently of each other.
 [[File:EN_Bei_T_1_1_S4neu.png|right|frame|Four-wire and two-wire transmission]]

@@ Line 99: / Line 99: @@
 # &nbsp; ISDN mixed mode,&nbsp;  which is understood to mean mixed simultaneous data transmission of texts and images,
 # &nbsp; ISDN T–Online with 64 kbit/s and transitions to T-Online in the analog telephone network as well as to group 3 and 4 telefax,
-# &nbsp; Video telephony – in practice,&nbsp;  however,&nbsp; only possible as slow moving image transmission,
+# &nbsp; video telephony – in practice,&nbsp;  however,&nbsp; only possible as slow moving image transmission,
-# &nbsp; Data communications using standardized protocols,&nbsp; such as file transfer with FTAM&nbsp; $($comparable,&nbsp; but technically not identical to the Internet service&nbsp; "FTP"$)$.
+# &nbsp; data communications using standardized protocols,&nbsp; such as file transfer with FTAM&nbsp; $($comparable,&nbsp; but technically not identical to the Internet service&nbsp; "FTP"$)$.