DE1000465B - Arrangement for connecting two-wire long-distance dialing lines without amplifiers with four-wire long-distance dialing lines with amplifiers - Google Patents

Description

The final state of expansion of a long-distance line 1 network for self-dialing remote service to a pure four-wire line between the exit and destination offices can only be achieved gradually. The carrier frequency systems, which are currently only being used to increase the number of lines in the district level, also offer four-wire routing up to the foothills of the transmission network, i.e. up to the district level. In addition to these four-wire speech paths, however, two-wire long-distance dialing lines must be operated equally in the same direction. It follows that alternating two-wire and four-wire long-distance dialing lines are lined up in a connection. Earlier planning did not require TF systems at the district level. The expansion of the transmission network was therefore geared towards the fact that only the transmission chain (connection between main office HA - central office ZA - central office ZA - main office HA) is formed from a four-wire line and thus a feedback circuit. With the use of carrier frequency systems in the district level, this four-wire long-distance transmission chain could be advanced via the node offices to the end offices with four wires in the future. For reasons of economy, one will be forced to keep terminal trunk lines and node trunk lines as two-wire lines in the district level. However, the aim must then be that when these two-wire lines are also used in the connection setup of the dial-up network, there is no appreciable increase in the residual attenuation compared to a pure four-wire dial-up connection. Stability can be endangered in particular if up to three feedback loops occur in addition to the previous single feedback loop in the pipeline chain in domestic traffic based on seven line sections. These three feedback loops occur when the end office lines (between node office KA and end office EA) are on TF systems on both sides of the four-wire long-distance line chain and the nodal office lines (between main office HA and node office KA) are two-wire lines.

According to the previous technology in the self-dialing remote service, the two-wire lines are connected to the four-wire transmission and reception paths of the long-distance line chain via permanently assigned forks using four-wire dialers. One is forced to supplement the two-wire lines with switchable extension lines on the four-wire side of the fork permanently assigned to it to the attenuation value that is necessary for reasons of stability for the four-wire long-distance line chain. In the send and receive paths of the four-wire dialer of the long-distance line chain, specifically on the side facing away from the fork, switchable extension arrangements for connecting two-wire long-distance lines without an amplifier also had to be used
Four-wire long distance dialing lines with
Amplifiers

Applicant:
Siemens & Halske Aktiengesellschaft,

Berlin and Munich,

Munich 2, Witteisbacherplatz 4,

and Standard Elektrik Aktiengesellschaft.

Stuttgart-Zuff enhaus en,

Hellmuth-Hirth-Str. 42

Julius Bugdahn and Dipl.-Ing. Wilhelm Ebenau,

Darmstadt,
have been named as inventors

Approximation lines are provided, which are switched on for the correct level interconnection of two four-wire lines will. These extension cables usually have higher attenuation values than those of the forks associated switchable attenuators. So far, however, there are no known switching technology solutions those in long-distance dial-up connections with three feedback loops, i.e. in the presence of LF node exchange lines, the residual attenuation by switching off the extension cables in the four-wire sections almost is brought to the attenuation value of the purely four-wire long-distance selection lines. The gain in residual damping in the case of pure four-wire routing of the long-distance dialing lines to the foothills of the network can in the case of composite connections for the district cable network to be made cheaper (e.g. by reducing the wire diameter) cannot be made usable. The residual attenuation of a long-distance dial-up connection with four-wire Through-connection of the line sections is dimensioned so that when idling at both ends a whistle safety of 0.2 N is available (idle technique). To increase the stability of the long-distance connection One tries to improve the temporal attenuation fluctuations of the transmission chain on a small Worth holding. But in order not to run the risk

This task can be solved with the four-armed and multi-armed voters available on the market.

The arrangement of the forks is taken from the system of "cutting technology". The forks are only 5 associated with the terminating transmission circuits of the four-wire lines, whereby the large saving of Forks for an internal district traffic is obtained. In contrast to the »separation technique« · the Feedback circuit with the new circuit arrangement

it has been ensured that there is no longer any whistling safety in the event of larger residual attenuation fluctuations, that partial windings of the fork transformer are short-circuited before the assignment and during the dialing of the number. This short circuit is z. B. but no longer effective during the implementation of the first election impulses Trigger states and for queries in private branch exchanges.

According to another method, the feedback loops are not only interrupted with a criterion for the called status before the occupancy and during the setting time. The transmission paths are not closed until the subscriber is posted, but rather are already in the eye of the subscriber who is called. The connection of the fork to the Vierstand switched through. This method, with "cutting wire line is referred to by the testing process of the selector for technology", provides for two-wire connection with known switching shocks, no switchable extension lines are derived from the means. The circuit arrangement is one of the four-wire interconnection points (central offices, "load technology", which also keep pace with the through main offices). They can be switched on for reasons of stability. The "load technology" requires individual line types El, Kl, Hl on different through-only fixed extension lines for level-correct output attenuation (o N in the long-distance line chain) Switching level of 0 N-like lines, the residual attenuation accumulates and prevails depending on. When connecting four-wire with two-wire number of interconnected lines for the lines is on the four-wire sides of the forks in addition to each total connection assumes different values. In the case of a fixed and one switchable extension line each, these fixed extension lines are maintained, which are switched on in the end service and switched off in the through service in relation to the control values at the entrance and exit. Only in exceptional cases can different levels be dispensed with on the TF systems, which means that switchable extension cables can be dispensed with, technically and with regard to the signal level of the end office, because here no four-wire, but rather system selection or tone selection is not desirable. The only two-wire through-connection is provided, the »separation technique« ■ has compared to the ν no-load technique «30 (see Fig. 1). The attenuation values of the switchable Verden have the advantage that the forks are only assigned to the four-wire extension line in the four-wire transmission path of the fork Vlgs lines and that the two-wire lines
are connected to each other with two wires in the node exchange
can. In contrast, with the »idle technology« ·
all two-wire lines that provide access to the four-35
must have wired cables equipped with forks.
It is then inevitable that, among other things, the
two-wire terminated trunk lines in the node office
four-wire through the voter. the

The number of forks required for this four-wire through-connection of the 40 in the four-wire transmission path of the fork Vlgf and in the four-wire internal traffic in the node office in addition to the reception path of the fork Vlkf depend on the four-wire dialer is considerably high compared to the input level f _e and the output level fi _a the complexity of the forks , which are actually only necessary for the switching four-wire line as well as the residual attenuation a _r , the wired speech paths of long-distance traffic, which are uniformly defined for all conversion of the two-wire speech paths into the four-wire connections. 45 is still just permissible with regard to stability. Regarding the question of an appropriate through-connection technology While the residual attenuation in the separation technology of four-wire and two-wire line sections, which accumulates in any order during line lines due to the non-use of switchable extension dial-up remote service, it can occur with the proposed connection setup, a circuit arrangement is based on one for all connection cases circuit arrangement proposed, as measured in Figure 1 50 equal value. This value can be reproduced. In this circuit arrangement, if a whistle safety of 0.2 N is maintained and the stability conditions are maintained, as will be shown later on the basis of a termination error attenuation of 0.4 N, a residual attenuation reduction between the ends of the connection to 0.8 N is measured two outermost end offices compared to the damping. The stability calculation will later be achieved in particular for the idle technology. 55 received. The connection cases with the same remainder are two-wire lines with four-wire lines via attenuation according to the circuit arrangement are reproduced in the selector for two-wire connection of the speech paths images i, 2,3,4,5, 6,6a, 7,8,9, gaund9b. It is therefore possible to choose the electoral levels that are low-frequency in addition to being in the district level

So far with three-armed rotary dials after the opposite end office line El also carrier-frequency end office line transition technology of the self-dialing remote service 60 lines El (TF) operated at the same time, one must be built in, with minor circuit changes, maintain the fixed constant residual attenuation value, if the same line type is due to the Switching technology, differ (see Fig. 4 a, for bundle reinforcement carrier-frequency lines shown in 9b and 10). The residual damping value 0.9 or 1.8 N must be translated. It is only required, but does not exceed the maximum allowable planning value. Interconnection of four-wire lines, which are not yet reconstructed in a district. At the exit of four-wire lines TF systems are used, it goes without saying that selectors are to be inserted on two-wire lines, which allow the remaining two-wire through-connection of the speech paths by suitable dimensioning of the switchable and four-wire through-connection as well as the fixed extension lines on the forks. 70 damping value of 1.8 N has to be reduced (see Fig. 10).

and Vlks are in the four-wire receiving path of the fork

a) in the transmissions of the terminal trunk lines equal to the residual attenuation value a _{r of} the connection,

b) in the transmissions of the node exchange, main exchange and central exchange lines to be selected equal to the attenuation a _{t of} the two-wire line involved in the passage.

The attenuation values of the fixed extension cables

10 amplifier output; the fork damping a _g has to be deducted from this.

^a Vlh _El = «r + Pa Cig

= 0.8 + 1 - 0.4 = 1.4 N.

Π. Node Office End Office Line (El)

1. Four-wire transmission path of fork.

_{a) Switchable} extension cable Vlgs _M.

Your attenuation value

corresponds to the value of the residual attenuation a _{r of} the connection

C-VIgS _n = «r

= 0.8 N.

b) Fixed extension cable VIgfei ■ Your attenuation value

In order to maintain the constant residual attenuation value, in our example of 0.8 N, for connections from the end office via the node exchange to the main office and vice versa, the two-wire node exchange lines Kl must be provided with an extension line VL if the end exchange lines are routed in TF systems (cf. Pictures 4 and 5). In the same way, the two-wire cross lines Ql between two nodal offices must be supplemented with an extension line VL if these cross lines are connected on both sides with end office lines that run on TF systems (see Fig. 6 a). The extension cable must be switchable because it must not be effective in all other connection cases (see Fig. 4 a, 6, 7 and 8).

If, in a main office area, low-frequency terminal trunk lines with low-frequency nodal trunk lines are operated in addition to carrier frequency lines, the extension lines of the nodal trunk lines cannot be switched off in the case of lines ending directly in the main office or going out from the main office. The residual attenuation is then, according to Figure 11, i, 3 N, but is still far below the permissible planning value. The extension lines VL can be switched off if the low-frequency node exchange lines are interconnected using two wires in the main office.

In contrast to the »idle technology«, there are no switchable extension lines VLp in the connecting line of the four-wire lines. Switchable extension lines are only found in the circuit arrangement at the transition points from two-wire lines to four-wire lines, and vice versa. The perfect contact of the rest contacts lying in the speech paths according to the loading technique can be ensured by known means of fritting. The newly developed high-pass forks allow the necessary direct current locking on the two-wire side. It can also be easily reached with the new local line transformers.

40

Dimensioning of the extension cables in the hybrid connections of the transmissions

I. End office

ι. Four-wire transmission path of the fork of the end office line (El). ^ Only fixed (non-switchable) extension cables

Much.

Your damping value ^ ₀

"-VlQEi

is equal to the sum of the residual attenuation value a _r

is equal to the difference between the input level p _{E of} the connection and the control value of the level p _a am at the two-wire terminals of the fork and the control amplifier output; of this, the fork damping a _{g is the} value of the level p _e at the amplifier input; the 55 and the fork damping a _{g must} still be deducted from this.

^a VIgei ⁼ (Pe - Pe) - ■ ^a g

= [o - (—2)] - 0.4 = 1.6 N. is equal to the sum of the residual attenuation value a _{r of} the connection and the amplification present in the four-wire transmission path of the El; the attenuation a _{g of} the two forks of the El and the attenuation of the other extension cables in the transmission path must be deducted from this. The amplification in the four-wire transmission path results from the difference in the control values of the levels at the amplifier output and amplifier input

A-a

[p _a - ft _e = + i - (—2) = 3 N]

- a A- (4> ■ * \ fa a

> ~ r 3 \ > τ

2. Four-wire receiving path of fork.

^a ) Switchable extension cable Vlks _Bl .

A- a. ™

^{As the VI} S ^s ei ■

^a viks _m = ^a r

b) Fixed extension cable Vlkf ^ your attenuation value

from the extension line Vlks _El :

2. Four-wire reception path of the fork of the end office line [El).

Fixed extension cable Vlk _M only. Your attenuation value

is equal to the sum of the residual attenuation value a _{r of} the connection and the control value of the level p _a am ⁼ ° ' ⁸ + ^{I) 0} ~ ^ ⁰ ' ^{4 +} ° ' ⁸ ^ = 0.6 N.

B. Node trunk line (Kl).

^τ - four-wire transmission path of the fork.

a) Switchable extension cable Vlgs _m .

Your attenuation value

corresponds to the attenuation U _{1 of} the terminal line

^a Vlgs _m = «l

= 0.5 N.

b) Fixed extension cable VIg fm- ⁵

Your attenuation value

^a vigt _cl

is equal to the difference between the input level ps at the two-wire terminals of the fork and the control value ^{10 of} the level p _e at the amplifier input; the fork damping a _{g must be} deducted from this:

^a Vlg1 _Kl = (Pe - Pe) - «j

= ι, ιΝ.

2. Four-wire receiving path of fork

a) Switchable extension cable Vlks _K i. _20th

Like the Vlgs _K i '.

^a Vlks _m = «i

= 0.5 N.

2. Four-wire receiving path of fork

a) Switchable extension cable Vl'ks _K i. Like the Vl'gs _m :

= 0.4 N.

b) Fixed extension cable Vl'kfsi · Your attenuation value

«■ VVk1 _Kl

is equal to the sum of the residual attenuation value a _r and the control value of the level p _a at the amplifier output; of these are the fork damping a _s and the damping

^a Vl'ks _m

to be withdrawn from the trunk line:

^a Wkf _Kl = K + Pa) - K + ^a Vl'ks _m )

= (0.8 + i) - (0.4 + 0.4) = ΐ, ο N.

b) Fixed extension line VIk fσ your attenuation value

3. Switchable extension line Vl in the low-frequency node trunk line Kl (Figures 4 and 5) and in the low-frequency cross line Ql (Figure 6 a).

Their damping value α, γι is equal to the difference between the residual damping value a _r and the damping value a _t of Kl or Qh

is equal to the sum of the residual attenuation value a _r 3 ° and the control value of the level p _a at the amplifier output; of which the fork damping a _g and the damping = a _r - H ₁
= 0.8 - 0.4 = 0.4 N.

^a Vlks _M

to be withdrawn from the trunk line:

^a Vlkf _Kl = («r + ίο) - (« β +

= (0.8 + ι) - (0.4 + 0.5) ' = 0.9N .

III. Main office
A. Node trunk line (Kl).

ι. Four wire transmission path of fork.

a) Switchable extension cable Vl'gs ^ i · Your attenuation value

^a Vl'gs _K i

corresponds to the attenuation a _{x of} the node exchange line 'κι ^{= a} i

B. Main Office Management (St.)
The attenuation values of the extension cables in the forks of the HI correspond to the values under A ,,

so

i. Four wire transmission path of fork

a) Switchable extension cable Vlgs _m :

40

45 a _{vlg $ m} = 0.4 N.

b) Fixed extension cable Vlgfm : a-vigf _m = 1.2 N.

2. Four-wire receiving path of the fork a) Switchable extension cable

= o, 4

b) Fixed extension cable VIkfm '■ = 1.0 N.

55

- 0.4 N.

b) Fixed extension cable Vl'gfzi-

Their attenuation value τ,. , · ™ · ·, ·· ,, · ,. ι_ · ..,. , "

Determination of the whistle safety in the most unfavorable

^a vi'kt _K i bond structure with successive two-wire and

is equal to the sum of the residual attenuation value a _r and four-wire long-distance dialing lines

the existing in the four-wire transmission path of the Kl amplifier 6o i. The whistle security (stability of the overall connection)

kung; of this, the damping a _{a of} the two forks _so ji are at least 0.2 N. This applies when considering

the claimant and the losses of the other in the _{transmission V} on level variations and unfavorable for the

Pull off the extension cables that are lying on the path. Frequency.

The reinforcement in the four-wire _{transmission path is according to 2} , a) According to CCIF (Comite Consultatif International

IL, A., i., B):

= 3N

_l )

- (2 a _B + a _V i'gs _m + «f / ü» _b + ^a vikf _El ) = 0.8 + 3 - (0.8 + 0.4 + 0.5 + 0.9) = 1 , 2 N.

Telefonique) the level fluctuation over time for each independently maintained section may not exceed ± 0.2 N; for η = sections is to be used:

a _r = ± 0.2 ·] / # N therefore for the five four-wire connections assumed in Figure 1

sections, of which three of these sections are in the middle of the connection and of the fourth and fifth sections separated by a two-wire line without an amplifier are:

«R = ± 0.2] / 5 = ± 0.45 N.

This value is distributed equally to the three feedback loops I, II, III; accordingly they are omitted on

Correspondingly, the FaU for

'r = o, i] / 6 f «0.245 N

5 and for the

Circle I: Aa _n - ±
Circle II: Δα _Τιι - ±
Circle III: Zl " _r ", = 4-

^ p = ± 0.09 N ^{Ί o.45}

Circle I: AcIi ₁ =
Circle II: AaIi _n =

0.245 x 5

= 0.204 N = 0.041 N

Pic 6.

In the case assumed in Figure 9,
= ± 0.27 N [Fig. Aai = Aa'i = 0.225 N Figure 9.

3. Taking into account the calculated in section 2

= ± 0.09 N nth surcharges result in the reinforcement numbers s

(negative throughput loss) for the individual At the six four-wire feedback circuits assumed in Büd 6 from the ones shown in Figures 1, 6 and 9 cut (five of these sections are from the sixth 20 specified level ratios to:

separated by a two-wire line without an amplifier) er s = φ φ ε + (Aa + Aa _r + AaL ')

if one holds in the same way: ^r

Aa = 4-05 N. Herein means

Pe = level at the two-wire terminals on the fork

This value is distributed over the two feedback inputs of the respective feedback loop considered,

circle I and II to p _Ä = level at the two-wire terminals of the fork on

Aa _r = ± 0.42 N output of the respective feedback loop under consideration.

_{un (} j _to ^r '' One obtains the following rounded or rounded up to o, o5N

Aa = +0.08 N. Reinforcement numbers, valid for each of the two over-

30 ways of carrying

In the case assumed in Figure 9 (five four-wire sections with two amplifierless two-wire end panels) there is only one feedback loop, i. H.

Aa ₁ . = Aa _Tl = ± 0.45 N Fig. 9,

is not to be divided.

b) According to experience, the residual attenuation of a line section increases with falling level by 0.01 N, i.e. systematic amplitude distortion for

a) in the circuit according to Figure 1:

Circle I: AaI ₁ = 0.01 1 = 0.01 N 1 Circle II: Aa ', _u = 0.01 3 = 0.03 N Circle III: Aa' _fm = 0.01 1 = 0, 01 N circle I: Aa ' _tl = 0.01 5 = 0.05 N circle Π: Αα' _Τκ = ο, οΐ ι = ο, οΐ Ν circle I: ZIa ^ ₁ = 0.01 5 = 0 , 05 N

Picture ι

Pic 6

Picture 9.

damping Circle ä I Reinforcement Numbers circle III every two «1 = in the «III = wireline 0.15 N 0.15 N U ₁ = 0.15 N 0.15 N 0.4 N 0.15 N 0.15 N 0.5 N 0.6 N Circle II Sn = 0.45 N 0.65 N 0.85 N

b) in the circuit according to Figure 6:

Attenuation of the
Two-wire line

c) According to CCIF, the residual attenuation may be 0.25 N less if the frequency deviates from 800 Hz than at 800 Hz. This applies to six sections. If, for the sake of simplicity, one calculates with unsystematic distortions, so these are with five four-wire sections - the distortions of the two two-wire sections are neglected (coiled cables) -

Aai = 0.1 y ~ 5 = 0.225 N.

If one distributes this value again in equal parts over the three feedback loops I, II, III, one obtains of residual attenuation distortion for the

0.4 N
0.5 N
0.6 N

Reinforcement digits in

Circle I.

0.25 N
o, 35 N.
0.45 N

Circle II

0.15 N 0.15 N 0.15 N

Circle I: AaIi ₁ =
Circle II: A a'i _u =
Circle III: Aai _m =

0.225
5

0.225
5

0.225 '

= 0.045 N

= 0.135

= 0.045 N

c) in the circuit according to Figure 9: Reinforcement digit
in the
Circle I.
S ₁ = 60 Cushioning each
Two-wire end field
"I = 0.70 N
0.90 N
1.10 N 65 0.4 N
0.5 N
0.6 N

Picture ι

4. It is likely that the simulation networks for the two-wire lines shown in the pictures so dimensioned that the error attenuation, which results from the accuracy of the correspondence of the alternating

Current resistance 5Ϊ of the network with the input resistance 3ß of the two-wire line results

= In

m—

ap ^ 2.3 N

is. This value applies to the operational termination of the two-wire line (fork of the connected feedback-locked Four-wire circle). Permissible adjustment error of this fork against 6oo ohms is <Ξ 0.15.

5. No absolute idle state (return loss a _Re = 0 N) is assumed at the ends of the overall connections shown in the figures. The return loss should

α-Re = 0.4N

if there are two-wire lines with an attenuation of U ₁ - 0.4 N each in the connection. In connections with two-wire lines each with α _τ S: 0.4. .. o. 6 N damping is with

«Äe = 0.5 N

expected. In local Local exchange trunks (oil) or connecting lines (Al) with a very small attenuation (about <0.2 N) these values can be achieved if necessary by homogenization.

6. The stability of the overall connection is determined by the feedback loop whose whistle

safety is lowest under the prevailing operational conditions. This is supposed to be the case for any feedback loop be examined in the connections according to Figures 1 and 9 (worst case), a) Feedback circuit II in Figure 1.

Importance and size of
ap see under 4.

URe - - 5

ai - 3 and 5.

si- - 3

Instead of si, S can also be used in the above equation. The following values are obtained for As:

Cushioning everyone
Two-wire line
^a z = Return loss
at each end of the
Overall connection Whistle safety
As = 0.4 N
o, 5 N
0.6 N 0.4 N
0.4 N
o, 5 N
0.5 N 0.23 N
0.19 N
0.31 N
0.22 N

b) Feedback circuit 1 or III in Figure 1.

The following applies to the whistling safety As of circle I or III:

As-

-S ₁ .

Meaning of the names given as under a).

The above equation applies to circle I, the above equation applies to circle II if one replaces sni with si and si with Sru. The following values are obtained for As:

Cushioning everyone
Two-wire line
^a l = Return loss
at each end of the
Overall connection
¹¹ JRe = Whistle safety
As = 0.4 N
0.5 N
0.6 N 0.4 N
o, 4 N
o, 5 N
o, 4 N
0.5 N 0.26 N
0.24 N
0.28 N
0.22 N
0.26 N

c) Feedback circuit I in Figure 6.

The following applies to the whistling safety As of circle I:

a _Re + In

-S ₁ .

Meaning of the names given as under a). The following values are obtained for As:

55

Attenuation of the
Two-wire line
^a l = Return loss
at each end of the
Overall connection
³ JJe = Whistle safety
As = 0.4 N
0.5 N
0.6 N 0.4 N
0.4 N
0.4 N 0.29 N
0.27 N
0.25 N

60 The following values are then obtained:

Attenuation of the
Two-wire line
U ₁ = Return loss
at each end of the
Overall connection
«Ite = Whistle safety
As = 0.4 N
0.5 N
0.6 N 0.4 N
0.4 N
0.4 N 0.47 N
0.39 N
0.31 N

40

e) Feedback circuit I in Figure 9. The following applies to the whistling safety As of the circuit:

As = hi

«, -« iie. 0 ~ ²

■ - si.

Meaning of the names given as under a). The following values are obtained for As:

Cushioning everyone
Two-wire line
«Z = Return loss
at each end of the
Overall connection
^a i2e = Whistle safety
As = 0.4 N
0.5 N
0.6 N 0.4 N
0.5 N
0.5 N 0.22 N
0.23 N
0.17 N ¹ )

65

^x ) As = 0.23 N, if a _{p is} based on 2.5 N rather than 2.3. When establishing a connection as shown in Figure 9, the two-wire lines may only be 0.6 N if it is possible to achieve error attenuation of 2.5 N with the simulation networks.

d) Feedback circuit II in Figure 6.

The equation under c) applies to the whistling safety As of circle II, if one substitutes for Sn = si and for si = sjx.

7. According to the explanations under 4., the replication networks at the forks of the four-wire lines for the continuing two-wire lines, i.e. for the Through case can be measured because individual replication is dispensed with in the circuit arrangement.

However, the same networks must also be retained in the end service because their switching is dial-up Causes difficulties. The gain digits in the two transmission paths of the four-wire lines are reduced to a nominal value of each when using these lines for the final service

s' = -0.8 N

reduced, because in this operating case the switchable attenuators assigned to the forks of the four-wire lines are effective. However, the surcharges calculated under 2., which are to be taken into account in the worst case of connection establishment according to Figure 9 a

Aa _n + AaIr ₁ + Aa _r [ «0.7 N

be. The stability calculation is therefore a reinforcement figure

s = s' + 0.7 = -0.1 N

20th

to be based on. Accordingly, in the end service at the fork points of the four-wire lines with the simulations determined for the case of passage, a return loss α R _e of only

au = As + s

= 0.2 + (-0.1) = 0.1N

to be present, which undoubtedly also with the above replication network is achieved.

Claims (3)

Patent claims: i. Arrangement for connecting two-wire long-distance dialing lines without amplifier with four-wire long-distance dialing lines with amplifiers, characterized in that that the four-wire side of the forks, which terminate the four-wire lines, have changeover contacts to the four-wire speech paths of these four-wire lines is only switched on after the two-wire line is connected to the two-wire side of the fork via the two-wire selector and the feedback circuit regardless of reporting the called connection after the load with the two-wire line is formed. 2. Arrangement according to claim 1, characterized in that on the four-wire side of the forks in series with fixed extension lines [Vlgf in the four-wire transmission path, Vlkf in the four-wire reception path of the fork) nor switchable extension lines {Vlgs in the four-wire transmission path, Vlks in the four-wire reception path of the fork) are arranged, which are switched on and off in the end service, and their attenuation values for the transmissions of the end office lines are equal to the residual attenuation value a _{r of} the connection, for the transmissions of the nodal exchange, main office and central office lines equal to the attenuation a _{x of} the two-wire line involved in the passage, while the attenuation values of the fixed extension lines are dependent on the attenuation value of the associated switchable extension line and also on the input level p _e or the output level p _{a of} the four-wire line and the residual attenuation a _{T, which is uniformly defined for all connections, which is just} de is still permissible. 3. Arrangement according to claim 1 and 2, characterized in that the replication networks are dimensioned so that with them at the fork points of the four-wire lines for the two-wire lines involved in the through service, error attenuation of at least ap = 2.3 N (= 10 ° / ₀ replica error) can be achieved and that the residual attenuation of the connection can be reduced to the nominal value a _r - 0.8 N with the same replicas when exiting the Local network return losses of at least aR _e = 0.4 N can be achieved. Considered publications:
German Patent Nos. 835 161, 867 254;
British Patent No. 458,436. In addition 6 sheets of drawings © € 09 740/157 12.56