Examples of Communication Systems/ISDN Basic Access - Revision history

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 The most common type of ISDN connection is the&nbsp; '''basic rate interface'''&nbsp; $\rm (BRI)$,&nbsp; which is used in particular by residential customers and medium-sized companies.
-[[File:EN_Bei_T_1_2_S1_neu.png|right|frame|ISDN reference configuration '''KORREKTUR: equipment''']]
+[[File:EN_Bei_T_1_2_S1_ganzneu.png|right|frame|ISDN reference configuration]]
 As shown in the diagram, an ISDN connection consists of the following functional groups:
@@ Line 160: / Line 160: @@
 $\text{Example 2:}$&nbsp;
 The graphic illustrates the difference between the&nbsp; "modified"&nbsp; and the&nbsp; [[Digital_Signal_Transmission/Symbolwise_Coding_with_Pseudo-Ternary_Codes#Properties_of_the_AMI_code|"conventional AMI code"]],&nbsp; namely the swapping of&nbsp; "0"&nbsp; and&nbsp; "1"&nbsp; in the binary signal.&nbsp; The reason for this interchange is:
-[[File:EN_Bei_T_1_2_S5.png|right|frame|AMI code and modified AMI code '''KORREKTUR: binary, after''']]
+[[File:EN_Bei_T_1_2_S5_neu.png|right|frame|AMI code and modified AMI code]]
 *With the conventional AMI code,&nbsp; no symbols are transmitted during a speech pause either.&nbsp; Or in other words,&nbsp; only pulses with the amplitude&nbsp; $0 \ \rm V$&nbsp; are transmitted over a longer period of time&nbsp; $($see middle diagram$)$.&nbsp; This makes clock synchronization more difficult.
@@ Line 174: / Line 174: @@
 The frame structure of the&nbsp; $\rm S_0$ interface - i.e. the bus between the network termination&nbsp; $\rm (NTBA)$&nbsp; and the subscriber terminal equipment&nbsp; $\rm (TE)$&nbsp; - is shown in the upper part of the following graphic.&nbsp; The lower part shows the frame structure in the opposite direction&nbsp; $\rm (TE&nbsp; → &nbsp;NTBA)$.
-[[File:EN_Bei_T_1_2_S6_ganzneu.png|right|frame|$\rm S_0$ frame structure '''KORREKTUR: code violations''']]
+[[File:EN_Bei_T_1_2_S6_v2.png|right|frame|$\rm S_0$ frame structure]]
 Each frame consists of
 *$2 · 8 = 16$&nbsp; bits for each of the two bearer channels&nbsp; $(32$&nbsp; bits in total$)$,
@@ Line 305: / Line 305: @@
 Each frame on the&nbsp; $\rm U_{K0}$ bus is made up of&nbsp; $120$&nbsp; ternary symbols and is transmitted in one millisecond. This results in a&nbsp; symbol rate of&nbsp; $120 \ \rm kBaud$.
-[[File:EN_Bei_T_1_2_S9_neu.png|rightr|frame|Frame structure of the&nbsp; $\rm U_{K0}$ interface '''KORREKTUR: Sync''']]
+[[File:EN_Bei_T_1_2_S9_v2.png|rightr|frame|Frame structure of the&nbsp; $\rm U_{K0}$ interface]]
 The graphic illustrates the&nbsp; $\rm U_{K0}$ frame structure,

@@ Line 240: / Line 240: @@
 The &nbsp;$\rm C$arrier $\rm S$ense $\rm M$ultiple $\rm A$ccess&nbsp; $\rm (CSMA)$&nbsp; method is used for blocking and unblocking the data channel and can be described briefly as follows:
-*The &nbsp;'''echo channel'''&nbsp; is inserted into the data stream for the direction&nbsp; $\rm NTBA → TE$.&nbsp; This is the totality of the &nbsp;$\rm E$&nbsp; bits marked in red in the graphic&nbsp; $($on the previous page '''KORREKTUR: section'''$)$,&nbsp; each of which transmits a previously received&nbsp; $\rm D$&nbsp; bit back to the terminals.
+*The &nbsp;'''echo channel'''&nbsp; is inserted into the data stream for the direction&nbsp; $\rm NTBA → TE$.&nbsp; This is the totality of the &nbsp;$\rm E$&nbsp; bits marked in red in the graphic&nbsp; $($on the previous section$)$,&nbsp; each of which transmits a previously received&nbsp; $\rm D$&nbsp; bit back to the terminals.
 *An &nbsp; &nbsp;$\rm E$&nbsp; bit&nbsp; results from the&nbsp; '''AND operation'''&nbsp; of all participants.&nbsp; This means: &nbsp;In the echo channel,&nbsp; the logical&nbsp; "1"&nbsp; only occurs if every participant reports a&nbsp; "1"&nbsp; - i.e. sends nothing.&nbsp; A&nbsp; "0"&nbsp; in the echo channel indicates that a device has access to the data channel or at least wishes to do so.
@@ Line 253: / Line 253: @@
 {{GraueBox|TEXT=
-$\text{Example 4:}$&nbsp; Two terminal equipments '''KORREKTUR: equipment'''&nbsp; $\rm TE1$&nbsp; and&nbsp; $\rm TE2$&nbsp; want to access the data channel at the same time.&nbsp;  They both wait for&nbsp; $N = 8$&nbsp; consecutive logical ones on the echo channel $($marked blue in the graphic, time marker&nbsp; $t_1)$.
+$\text{Example 4:}$&nbsp; Two terminal devices&nbsp; $\rm TE1$&nbsp; and&nbsp; $\rm TE2$&nbsp; want to access the data channel at the same time.&nbsp;  They both wait for&nbsp; $N = 8$&nbsp; consecutive logical ones on the echo channel $($marked blue in the graphic, time marker&nbsp; $t_1)$.
 [[File:EN_Bei_T_1_2_S6b.png|right|frame|Data channel access and interaction with the echo channel]]

@@ Line 107: / Line 107: @@
 [[File:EN_Bei_T_1_2_S4a.png|right|frame|$\rm S_{\rm 0}$ bus and connection options]]
-Up to eight terminal devices '''KORREKTUR: equipment''' such as telephones,&nbsp; fax machines,&nbsp; ISDN cards and also ISDN private branch exchanges can be connected simultaneously to a maximum of twelve connection sockets.
+Up to eight terminal equipment such as telephones,&nbsp; fax machines,&nbsp; ISDN cards and also ISDN private branch exchanges can be connected simultaneously to a maximum of twelve connection sockets.
 Such an &nbsp;'''ISDN multiple subscriber line'''&nbsp; has:

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 # The logical&nbsp; (binary)&nbsp; "1"&nbsp; is represented by the voltage value&nbsp; $0\ \rm  V$&nbsp; and the logical&nbsp; (binary)&nbsp; "0"&nbsp; alternately by &nbsp; $+s_0$ &nbsp; or &nbsp; $-s_0$,&nbsp; as the comparison of the upper and lower signal waveforms in the graphic of&nbsp; $\text{Example 2}$&nbsp; shows.&nbsp; For ISDN,&nbsp; the modulation range&nbsp; $s_0 = 0.75\ \rm  V$&nbsp; is fixed.
 # The pseudo-ternary coding ensures that the&nbsp; $\rm S_0$&nbsp; bus remains free of DC voltage at all times.&nbsp; The redundancy of &nbsp; $1 - 1/\log_2 (3) ≈ 37\%$ &nbsp; is used in ISDN,&nbsp; for example,&nbsp; for frame synchronization by deliberately violating the AMI coding rules to mark frames.
-# The&nbsp; $\rm S_0$ bus is writable by the logical&nbsp; "AND"&nbsp; operation.&nbsp; This means that the NTBA only receives the logical&nbsp; "1"&nbsp; if all terminal devices '''KORREKTUR: equipment''' send a logical&nbsp; "1" - i.e. the zero level.&nbsp; If only one device sends the logical&nbsp; "0",&nbsp; this is also received.
+# The&nbsp; $\rm S_0$ bus is writable by the logical&nbsp; "AND"&nbsp; operation.&nbsp; This means that the NTBA only receives the logical&nbsp; "1"&nbsp; if all terminal devices equipment send a logical&nbsp; "1" - i.e. the zero level.&nbsp; If only one device sends the logical&nbsp; "0",&nbsp; this is also received.
 # All terminal equipment obtains its clock from the NTBA and operates bitsynchronously.&nbsp;The quiescent signal is always the zero level,&nbsp; i.e. the logical&nbsp; "continuous one".&nbsp; In addition,&nbsp; since all devices in the data channel always transmit a&nbsp; "0"&nbsp; with same polarity,&nbsp; pulses cannot cancel each other out.

@@ Line 78: / Line 78: @@
 <br>
 There are two different types of terminal equipment for ISDN:
-*'''Terminal Equipment Type 1'''&nbsp; $\rm (TE1)$: &nbsp; This includes,&nbsp; for example,&nbsp; ISDN-capable telephones,&nbsp; ISDN group 4 fax devices and ISDN PC cards.&nbsp; These terminal equipments '''KORREKTUR: equipment''' are connected directly to the&nbsp; $\rm S_{\rm 0}$&nbsp; interface via the network termination&nbsp; $\rm (NTBA)$.&nbsp;
+*'''Terminal Equipment Type 1'''&nbsp; $\rm (TE1)$: &nbsp; This includes,&nbsp; for example,&nbsp; ISDN-capable telephones,&nbsp; ISDN group 4 fax devices and ISDN PC cards.&nbsp; These terminal equipment are connected directly to the&nbsp; $\rm S_{\rm 0}$&nbsp; interface via the network termination&nbsp; $\rm (NTBA)$.&nbsp;

@@ Line 266: / Line 266: @@
 <br>
 According to the&nbsp; [[Examples_of_Communication_Systems/ISDN_Basic_Access#Some_explanations_of_terms|"ISO-OSI reference model"]],&nbsp; the&nbsp; $\rm U$ interface is generally the connection between the network termination&nbsp; ("Network Termination for ISDN Basic rate Access",&nbsp; $\rm NTBA)$&nbsp; and the line termination&nbsp; $\rm (LT)$&nbsp; in the exchange.
-*In the case of the ISDN basic rate interface,&nbsp; this point is called the&nbsp; die $\rm U_{K0}$ interface and the associated bus the&nbsp; $\rm U_{K0}$ bus.&nbsp; "$\rm K$"&nbsp; stands here for the transmission medium&nbsp; "copper"&nbsp; and &nbsp;"$0$"&nbsp; for the basic rate interface.
+*In the case of the ISDN basic rate interface,&nbsp; this point is called the&nbsp; $\rm U_{K0}$ interface and the associated bus the&nbsp; $\rm U_{K0}$ bus.&nbsp; "$\rm K$"&nbsp; stands here for the transmission medium&nbsp; "copper"&nbsp; and &nbsp;"$0$"&nbsp; for the basic rate interface.
 *The line termination&nbsp; $\rm (LT)$&nbsp; forms the transmission-technical termination on the network side.&nbsp; It handles all switching and operational tasks,&nbsp; line coding,&nbsp; transmission control,&nbsp; remote power supply,&nbsp; and test and monitoring functions.

@@ Line 257: / Line 257: @@
 # &nbsp; After that,&nbsp;  both send&nbsp; &ndash; again simultaneously &ndash;&nbsp; a flag&nbsp; $($green mark,&nbsp; time marker&nbsp; $t_2)$.
-# &nbsp; At time&nbsp; $t_3$,&nbsp; both terminals send their information.&nbsp; In the echo channel,&nbsp; a collision is odetected if the bits of TE1 and TE2 differ.
+# &nbsp; At time&nbsp; $t_3$,&nbsp; both terminals send their information.&nbsp; In the echo channel,&nbsp; a collision is detected if the bits of TE1 and TE2 differ.
 # &nbsp;  The logical&nbsp; "0"&nbsp; has priority over the logical&nbsp; "1".&nbsp; In the example,&nbsp; TE2 has priority over TE1,&nbsp; because the fifth bit of TE2 is a&nbsp; "0"&nbsp; and the fifth bit of TE1 is a&nbsp; "1"&nbsp; $($red marks$)$.
 # &nbsp; Thus TE1 will stop the transmission.&nbsp; It can only send its information at time&nbsp; $t_7$&nbsp; after TE2 completes its transmission with a flag&nbsp; $(t_4)$,&nbsp; and thus the data channel is free again from&nbsp; $t_5$.&nbsp;