DE1253764B - Signaling method for an intercontinental telephone system with TASI transmission channels - Google Patents

Description

GERMAN WTWWI PATENT OFFICE

EXPLORATION PAPER H04m

German class: 21 a2 - 36/06

Number: 1253 764

File number: St 21620 Vin a / 21 a2

1 253 764 filing date: January 29, 1964

Opened on: November 9, 1967

The invention relates to a signaling method for an intercontinental telephone system, in which one Number of transmission channels is used for a larger number of call connections.

The introduction of underwater telephone cables over very long distances has to be introduced of a new transmission method in which a transmission channel is not assigned to a connection will. Such a transmission method is known as the TASI method (Time Assignment Speech Interpolation) became known. The TASI method is based on the fact that during a normal Conversation is occupied with speech for less than half the conversation time. The rest of the time is for them Signaling is provided and consists of the pauses between syllables, words and sentences. Another considerable amount of time elapses between the termination of the language of the one person and the one Start of speech from the other person. The TASI method uses these pauses and dead times ao a call connection to the transmission channel for other call connections to make available who just have to transmit speech.

In practice, the number of calls in a TASI system can be roughly double be chosen as large as the transmission channels are provided. Via a system with 36 transmission channels 72 calls can be made, with one for each call at any given time free channel can be found. In the worst case, the loss of speech is so small that none noticeable deterioration in speech quality occurs.

1 shows a basic circuit diagram of a TASI system in which 72 line connections are routed to 36 transmission channels CHI ... CH36. The 36 channels are in most cases carrier frequency channels on a single coaxial cable. The LTE devices are the individual line circuits, and the TASI-EQUPT circuits represent all the devices required for TASI conversion.

A feature of the TASI system is the signaling that occurs with every call connection. The signaling includes the dialing signals, the ringing tone, the starting signal, the subscriber busy tone, etc. The signaling time is absolutely necessary in a telephone system. It takes up a small part of the talk time. If tone-frequency signaling is provided, then there is the possibility of signal imitation through speech. The signaling method for an intercontinental telephone system with
TASI transmission channels

Applicant:

International Standard Electric Corporation.
New York, NY (V. St. A.)

Representative:

Dipl.-Ing. H. Ciaessen, patent attorney,
Stuttgart W, Rotebühlstr. 70

Named as inventor:
Esmond Philip Goodwin Wright,
Bishops Stortford, Hertfordshire
(Great Britain);

Martinus den Hertog, Brasschaat (Netherlands)

Claimed priority:

Great Britain March 8, 1963 (9305)

Signal evaluation times must therefore be increased, so that the efficiency of the TASI system is reduced.

In the known TASI system according to FIG. 1, the signals are transmitted via the occupied ones Transmission channels. Since these transmission channels are not permanently assigned to a call connection, Reliable signaling over the TASI route causes considerable difficulties. It's just supposed to it should be pointed out that brief interruptions in a signal trigger the occupied Transmission channel and a reassignment of another transmission channel occurs, which inevitably occurs leads to incorrect signaling.

It is also known to have signals for several transmission channels on a common signal channel summarize.

The object of the invention is to create a signaling method for a TASI system that uses the TASI transmission channels Completely relieved of the signaling and yet the clear assignment The signals to the lines are also guaranteed on the receiving side of the TASI line. The signaling method for an intercontinental telephone system with TASI transmission channels is according to of the invention characterized in that the

709 687/294

Signaling devices on the lines in front of the TASI devices from the other line circuits are separated and that the signals present there in the time division multiplex method in per se known Way via a common one of the transmission channels provided for voice transmission separate transmission channel. It can also be provided that the separate signal channel during the time in which no signals for the telephone channels are to be transmitted, is used as a separate data transmission channel.

The invention is illustrated with reference to FIGS. 2 explained in more detail. The difference to the TASI system according to FIG. 1 is that the CH36 channel is used as the signal channel. The 72 lines are distributed to channels CHI to CH 35.

In each line, the signaling devices SIG are shown separately from the rest of the line circuit LTS. These devices are connected to common devices B and D , the signals of which are fed to the TASI conversion device TASI-EQUPT for transmission on the channel CH 36 (SIG) . The same devices are connected on the other side of the transmission path.

In intercontinental telephone systems, the line transmissions contain a type of signal memory, that feed special signals on the intercontinental section, and the various Line sections often have different signaling methods.

The number of trunk lines that can be served by a particular signal channel depends the number and duration of the signals to be transmitted and the permissible signal delay away. It is unlikely that in the main call time the number of Signals exceeds the number of channel shutdowns in the TASI system.

The introduction of a medium speed data transmission system in place of voice frequency transmission allows all signals for a considerable number of voice connections to be transmitted over one channel.

Such a data transmission system is almost two orders of magnitude faster than the usual Line signals on TASI channels and about an order of magnitude faster than the usual multi-frequency coding methods when signaling from register to register.

Line and register signals only need to be pending until they have the information they want mark, have transferred. It is not necessary to expand the signals to have a cover long delay time. This would be insufficiently tested. With respect to register signals exists complete freedom of movement, the characters, regardless of a likelihood of being late Access, transfer.

The number of possible signals that can be transmitted in a data transmission process, is very large, so that the use of such a method appears particularly advantageous there, where many signals are needed.

A special signal channel with data transmission methods is normally used to transmit the Signals used from one section to the other. This repetition of the signals can be either via a register or directly from section to section. It is beneficial if everyone

Receiver remains permanently connected to the same signal channel.

The register in the outgoing intercontinental office remains switched on so that the control of the intercontinental connection remains very flexible. With such an outgoing register control Any type of overlapping switching operations can be used. The dialing characters can in a block, individually or in any arbitrary

ίο combination can be transmitted. This only depends on the fact that the break after the election until Reporting of the participant is shortened.

The difficulties that arise due to the different length of national key figures can be found in can be avoided in many cases by a backward sign to the register in the exit office if this Character acknowledges receipt of the code. The receipt of this backward character can limit the 4-second protection time, which had to be inserted there,

make ao superfluous. The waiting time after the election is therefore shortened.

Reverse signals can also be used to indicate errors, so that connections can still be established. Appropriate national tones can be added to such signals so that the caller can also be identified. In other cases, these signals can also be used to initiate a second attempt to establish a connection. Another advantage of register control from the exit office is that the routes or directions used for the connection can be displayed via the reverse signals. Regardless of whether the reverse signals are used to re-establish a connection, there is an advantage from the point of view of the maintenance personnel that each international office can identify the point from which a connection cannot be established. In the case of a world telephone network, in view of the language difficulties it is particularly necessary that this report be transmitted back to the country of origin.

Faster line signaling is important as it creates the possibility of the speech path in time for the answer to be established. Since the speech path is not used for signaling, the delay caused by the intercontinental system is equal to the time it takes for the start sign required to the following national or continental system with signaling over the speech channel.

The use of a special channel for line and register characters does not bring any burden of the speech channels while the connection is being established. Correspondingly measured busy tones also provide no burden for the speech channels. Also occasional attempts to establish a connection by one participant or a group of participants do not cause any overloading of the speech channels.

Simple means for sending monitoring signals are also assigned to the particular signal channel. These signals are not assigned to any particular speech path.

If a signal channel is used for several connections, then each signal must have one Address to be added. A signal with twelve elements can be both the signal and the Represent address. The duration of such a signal is of the order of 10 ms. this corresponds to a reduction by two orders of magnitude

Claims (5)

line signals and an order of magnitude reduction in register signals. A new intercontinental signal system should also enable data transmission via switched connection paths. In many cases, this data is only a short message. The terminal equipment for data subscribers will always be more expensive and larger than for telephone subscribers and mostly also telex subscribers. A special signal channel offers the possibility that a data call is handled quickly and that the start character is also transmitted back very quickly. The consequence of this is that the occupancy time of the registers becomes small and the intercontinental circuits can be used effectively in spite of the fact that the message downtime is short. The use of a special signal channel has the effect that the allocated speech channels are not subject to any restrictions with regard to the bandwidth for the exchange of messages. When signaling in the voice band, it is not possible to use the same type of signaling method as is used in any form for data transmission. If the particular signal channel is not sufficiently loaded by the signals from the telephone channels, then it is possible to use this channel for data transmission as well. The two traffic flows can be merged on the outgoing side and separated on the incoming side via suitable elimination circuits. Data memories are to be provided at both ends, which are necessary for speed change and error correction. The memories also allow the data transmission to be interrupted when there are telephone signals. These facilities are shown in FIG. 2 indicated by the devices ^, B and D and the dashed line "data channel". In some cases the intercontinental circuits go beyond the facilities of the TASI system. The separate signal channel usually ends at the same points as the TASI line. The signaling must be forwarded in this case. The signals can be forwarded via another separate signal channel of the following system. This channel must enable rapid signaling over the entire intercontinental section. Patent claims: 1. Signaling method for an intercontinental telephone system with TASI transmission channels, characterized in that the signaling devices (SIG) of the lines (Ol to 72) in front of the TASI devices (TASI-EQUPT) are separated from the other line circuits (LTE) and that the lines there pending signals can be transmitted in a manner known per se via a common transmission channel (CH 36) that is separate from the transmission channels (CHI to CH 35) provided for voice transmission using the time division multiplex method. 2. The method according to claim 1, characterized in that the separate signal channel (CH 36) in the time in which no signals for the telephone channels are to be transmitted, as its own Data transmission channel is used. 3. The method according to claim 1, characterized in that the signals for the telephone channels contain the signal meaning and the address on the common signal channel. 4. The method according to claim 2, characterized in that the common signal channel (CH 36) elimination switching means (B, D) for telephone and data signals and a buffer memory (A) are assigned for data signals. 5. The method according to claim 2 and 4, characterized in that when signals occur for the telephone channels the data transmission is interrupted and the incoming data get saved. Considered publications:
German Patent No. 761462;
U.S. Patent No. 2,881,251. 1 sheet of drawings 709 687/294 10. 67 © Bundesdruckerei Berlin