DE1010116B - Arrangement for the interconnection of long distance dialing lines - Google Patents

Description

GERMAN

It is well known that the future self-dialing telecommunication service intends to use four-wire long-distance lines to connect four-wire with each other via selector in order to reduce the throughput attenuation to 0 N at the same time with regard to the Whistle safety, the number of feedback circuits compared to the two-wire connection to only one Decrease feedback loop. To these four-wire led reinforced long-distance lines with two-wire to be able to get on and off led lines in every office, will be according to the previously known Technology, the two-wire lines are equipped with a fork and additional switchable extension lines. These switchable extension cables are used to double-wire the different lengths routed lines to uniform attenuation values to complete. They are also dimensioned so that their values match those of the switchable extension cables of the Remote selection lines the minimum residual attenuation of the overall connection required for stability or the echo result. The disadvantage of this method is that in the four-wire long-distance dialing lines In addition to the switchable extension cables, fixed extension cables can also be connected in series have to and for the most part still switchable on the four-wire sides of the forks that are switched on via dialers Extension lines are arranged. For switching the switchable extension cables on and off One contact in the longitudinal branch and one contact in the transverse branch, i.e. a total of three contacts, are necessary. There are at least six contacts in the through-connection of a voice connection, usually twelve contacts involved in connection case. These contacts of the switchable extension cables result, among other things the following three unfavorable malfunction possibilities.

a) Series resistance in the branch bridged, series resistance in the δ branch not bridged, transverse resistance separated;

b) series branch in-wire bridged, series branch in α-wire not bridged, transverse resistor switched on;

c) Series resistance in a- and δ-core not bridged, transverse resistance switched off.

■ The principle of the switchable extension cable is shown in Figure 1. Except for the circuitry with switchable extension lines when interconnecting lines in the self-dialing remote service yet another method is known in which to interconnect four-wire long-distance dialing lines with two-wire unreinforced cables, fixed extension cables, not switchable, are used can be used to achieve the necessary residual attenuation of the overall connection. In this procedure are the trunk lines on the input side with an outgoing transmission and on the output side with a Arrangement for the interconnection of long distance dialing lines

Applicant: Siemens & Halske Aktiengesellschaft,

Berlin and Munich,

Munich 2, Wittelsbacherplatz 4,

and Standard Elektrik Aktiengesellschaft,

Stuttgart-Zuff enhaus en,

Hellmuth-Hirth-Str. 42

Wilhelm Ebenau, Darmstadt, and Julius Bugdahn, Darmstadt, have been named as inventors

incoming transmission, which has the ability to switch the long-distance selection line to the selector for four-wire through-connection via changeover contacts or to the same selector for two-wire through-connection via forks. Fixed extension cables are assigned to the fork to achieve the necessary switching level. The fixed extension cable VLg on the four-wire side and the forks Ga ₁ and Ga ₂ (see Fig. 2) usually have an attenuation value of at the usual amplifier input levels fi _e = -2 N due to the fork attenuation a _{g = 0.4 N} avi _g = ß = - p_e ~ a _g = - (- 2) - 0.4 = 1.6 N

To achieve the necessary residual attenuation for connections in the district level, fixed extension lines VLt are arranged in addition to the extension line VL ^ on the incoming side of the forks Ga ₁ and Ga ₂ in the outgoing four-wire paths behind the changeover contacts. B. of 0.2 N for terminal trunk lines (El) and 0.4 N for node trunk lines (Kl), aligns (see Fig. 3).

With the damping values given for the VLt in El and Kl (0.2 or 0.4 N), the following residual damping values are obtained:

District traffic:

Connection El + El.: -. = 0.4 N

El + Kl . ........ = 0.6 N

E1 + K1 + E1 = 0.8 N

El + Kl + Kl + El = 1.2 N "

709 548/155

Long-distance traffic: As in district traffic, there is attenuation of the pipeline chain is 0 N.

According to the circuit arrangement of the extension line shown in Figure 3, on the other hand, the residual attenuation of a connection from an end office at the seat of HA 1 (ZA 1) to an EA at the seat of HA 2 (ZA 2) would only be ON; this value differentiates the minimum value of the residual attenuation calculated for stability and echo. The stability and echo conditions for such connections are met in the circuit arrangement shown in Figure 4.

The invention avoids the insertion of extension cables VL _t in the four-wire paths and thus the accumulation of the residual attenuation in the case of four-wire interconnection of several remote dialing lines by arranging the fixed extension line determining the residual attenuation between the incoming four-wire side of the connectable fork and the changeover contact at the output of the four-wire line. It also aims to ensure that the residual attenuation a _r (in our example = 0.8 N) when establishing a connection with only one long-distance dialing line is equal to the remaining attenuation when establishing a connection via several long-distance dialing lines (see Fig. 4). The invention also has the advantage that the switch-through level 0 N prevails at the switch-through points in the transmission and reception path of the selector and the input and output levels of -2 and -J-IN required for the individual line sections regardless of the number of interconnected , reinforced long-distance dialing lines are retained. This is achieved in that the extension line VLjc on the incoming four-wire side of the forks Ga ₁ and Ga ₂ receives the following value at an output level of the line section φα (ζ. B. + IN) and the required residual attenuation a _r:

aVLTc = «r - ^a g + ta ·

= 0.8 - 0.4 + 1 = 1.4 N (see Büd 2)

The attenuation value of the extension cable FL & is therefore dependent on the minimum value of the residual attenuation a _r to be required with regard to stability and echo, the size of which will be determined in a later section.

It is known (German patent specification 910 912), two-wire lines leading to four-wire lines To connect fork transmissions with one another with two wires, eliminating the line replicas. With the avoidance of the accumulation of the residual damping, as well as with the solution according to the invention by laying the fixed cable extension that determines the residual attenuation between the switchable one The known arrangement has nothing to do with the four-wire fork and its switchover contacts.

It is also known (German Patent 875 216), two four-wire lines, which are also two-wire-like via forks can be connected to each other via four-wire dialer directly, with the Forks, however, for the purpose of monitoring the connection at a remote place with high resistance to the four-wire lines stay on. This arrangement is also not concerned with the task underlying the invention, to avoid accumulation of the residual attenuation when connecting several four-wire line sections. Nor does it show the solution feature of the invention.

There are also arrangements for interconnecting several reinforced two-wire and four-wire lines known (German Patent. 715 995), in which the gain is adjusted so that the attenuation from switching point to switching point is 0 N for four-wire lines and 0.2 N for two-wire lines. These arrangements However, due to the inadequate homogenization of the lines, appropriate line extensions can be used on the two-wire or four-wire side of the forks no longer those for a larger number of four-wire line sections lying one behind the other meet the necessary stability conditions, such as those required for modern long-distance dialing networks are required. They, too, therefore have an insertion of the residual attenuation determining line extensions, as proposed by the invention, does not.

Determination of the minimum values of the residual attenuation of a feedback circuit consisting of 1, 3 and 7 line sections

1. The whistle safety (stability) of the feedback loop should be at least 0.2 N. This applies when taking level fluctuations into account and for the worst frequency.

2a) According to the CCIF (Comite Consultatif International Telephonique), the level fluctuation over time for each independently maintained section may not exceed ± 0.2 N, for η sections the following should be used:

Aa _r = ± 0.2] / «N,

so for 1 section:
"3 sections:
,, 7 sections:

± 0.2ON, «± 0.35 N, w ± 0.54 N.

b) According to existing experience, the residual attenuation of a line section decreases by 0.01 N with decreasing amplitude, i.e. systematic amplitude distortion in η separately monitored circuits

ZIiJr ₂ = 0.01 -MN,

so for 1 section: 0.01 N, "3 sections: 0.03 N, "7 sections: 0.07 N.

c) According to CCIF, the residual attenuation at a frequency deviating from 800 Hz may be 0.25 N less than at 800 Hz. This applies to 6 sections. If, for the sake of simplicity, one calculates with unsystematic distortions, these are sections at η

= 0.25

= 0.1

1/6

so for 1 section:
"3 sections:
"7 sections:

0.10N, 0.17 N, 0.25 N.

3. To maintain the stability, taking into account the additions under 2 a) to 2 c), the residual attenuation a _{r of} a feedback circuit that is not closed at its fork points (return flow attenuation a _R = 0 N) is obtained

1 section 3 sections 7 sections A,
+ Aa _n
+ A (Ir ₂
+ Aa _r , 0.20
0.20
0.01
0.10 0.20
0.35
0.03
0.17 0.20
0.54
0.07
0.25 a _r . 0.51 N 0.75 N 1.06 N

4. If at the fork points of the feedback circuit named under 3, instead of the return loss «h = 0N assumed there, a value of 0.4 N is used (when the two-wire line firmly connected to the fork is homogenized), the minimum values calculated under 3 for the Residual damping a _{r can} be reduced by 0.4 N, i.e.

1 section

0.11 N

3 sections

0.35 N

7 sections

0.66 N

5. It must be checked whether the residual attenuation values specified under 3 and 4 are still permissible with regard to echo are.

The echo transit time is made up of the cable transit time and the filter transit time. B. for a length of 1000 km (maximum distance in Germany) 220 km / ms group speed (multi-channel carrier frequency system) and 1.25 ms filter delay per section for η section

_o 1000 km

² · - ^ inT, -ϊ l · 2 · μ · 1.25 ms.

220 km / ms

Echo delay ....

1 section

11.5 ms

3 sections

16.5 ms

7 sections

26.5 ms

The associated, at least required, echo attenuation is based on a C. C. I. F. curve

Echo delay

1 section

0.5 N

3 sections

0.7 N

7 sections

1.1 N

These values apply when taking into account the level fluctuations under 2 a) and 2 b) according to the most unfavorable side. If one also takes into account the return attenuation αχ occurring at the hybrid circuit at the far end, which is to be taken into account according to CCIF with 0.7 N, one obtains the minimum residual attenuation of a feedback circuit that is required with regard to the echo

he - & R

(a _E - 0-r) ..
+ Aa _n ..
a _r :

Va

1 section

0.5

-0.7

- 0.2

-0.1
0.21 N
Ο, ΙΙΝ

3 sections

0.7 N - 0.7 N 0 0

0.38 N 0.38 N

7 sections

1.1 N

- 0.7 N

+ 0.4 N

+ 0.2 N

0.6ON

0.80N

- (Ir) + [Aa _n + Aa _r ,)

6. From the results under 3, 4 and 5 it follows that, with regard to stability and echo, the following minimum values of the residual attenuation a _{r are} to be required:

1 section N 3 sections 7 sections 0.51 N 0.75 N 1.06 N ²⁰ Idle technology
(«Β = ON) ... 0.11 0.38 N 0.8ON load jstechnik
0.4N) ..

7. The residual damping value of 0.8 N determined for 7 sections above is in our example also used as a basis for the individual circuits and for the overall connection. This brings essential operational metrology Advantages in maintaining the trunk line network.

Claims (1)

PATENT CLAIM: Arrangement for the interconnection of long-distance selection lines with amplifiers among each other and of long-distance selection lines with amplifiers with lines without amplifiers, taking into account the stability and echo conditions, in which the accumulation of residual attenuation is avoided when interconnecting long-distance selection lines, characterized in that the fixed extension line (VL _k ) is arranged between the incoming four-wire side of the connectable fork and the changeover contact at the output of the four-wire line. Considered publications: German Patent Nos. 715 995, 875 216, 910 912. In addition 3 sheets of drawings