Time-division Switching Network Research Articles

Continuous-wave operation of monolithic two-modeoptical flip-flop with etched laser mirrors

The authors report continuous wave operation of a monolithic two-mode optical flip-flop with orthogonal light outputs. Bistable states with large ON/OFF ratios are demonstrated. The states can be switched with short electrical pulses. The device could function as an optical memory in future time-division switching networks.

An expandable time-division circuit switching LSI and network architecture for broadband ISDN

A broadband network architecture is proposed that integrates multimedia services, such as data, video, and telephony information, using 52-Mb/s based STM-paths at the user network interface (UNI). The user can access any new service via the STM-based access network via either synchronous transfer mode (STM) switching or asynchronous transfer mode (ATM) switching. STM circuit switching supports long duration, constant bandwidth data transfer services such as video and high-definition television (HDTV) distribution and will also be used for the crossconnect system. Circuit switching can provide transparent transmission during long connection periods. This paper also proposes an expandable time-division switch architecture, an expandable time-division switching LSI, and an expandable switching module for small to large size system applications. The proposed time-division switching LSI, module, and system handle 52-Mb/s bearer signals and have throughputs of 2.4 Gb/s, 10 Gb/s, and 40 Gb/s, respectively. The time-division switch realizes video distribution with 1:n connections. Finally, a local switching node that features an expandable 52-Mb/s time-division circuit switching network is shown for multimedia access networking.

N:1 connection switching networks suited for time division switching

Two types of n:1 non-blocking switching networks are proposed. One is the Cascade Clos Network, which is non-blocking under the condition of simultaneous origination of multiconnection calls. The other is the Cascade Benes Network, which is rearrangeable non-blocking. Then, both switching networks are applied to TSTST time division switching networks. Both networks can also be combined in TSTST configuration. This is very flexible and suitable for a multi-service switching network in broadband-ISDN.

On combinatorial properties of broadband time-division switching networks

The conditions under which various structures of broadband time-division switching networks are nonblocking and rearrangeable are presented. It is also shown that three structures of triangular networks are isomorphic.

High-Speed Time Division Switch for 32-Mbit/s Bearer Rate Signals

This paper describes the high-speed time division switch employed in a 32-Mbit/s bearer signal communications system. System performance is realized by using three technologies. The first is a switch structure referred to as a 2-RAM 2-bank structure which ensures high-speed performance by increasing switching throughput four times over that of the basic structure. The second is the inclusion in the switch of two types of peripheral logic developed using Si-bipolar super-self-aligned process technology. The third is high-speed synchronous transmission of data. A large channel capacity time division switching network is also discussed. In conjunction with the network, these technologies make it possible to realize the ISDN time division switches necessary for such services as TV and high-definition TV communications.

A proposal of time division switching network using variable time slot multi/demultiplexing circuit

AbstractThis paper presents a time division switching network in which only functionally expanded multiplexing switches are connected in cascades. It has been designated Variable Multi‐demultiplexing Time Division Switching Network (VTDS). Input multiplicity is commonly one in the conventional multiplexing switch (switching circuit element); however, the one proposed herein accommodates lines whose multiplicity is more than one. All VTDS holding memories, which store the correspondence between input timeslots and output timeslots, can be realized with the same economical low‐speed memories. Moreover, the switching network structure is optimized assuming that gate cost is proportional to gate speed. the optimum VTDS switch size gradually decreases towards the center stage. an outstanding VTDS feature is that multiplexing switching gate speed can be utilized most effectively because VTDS needs no time memory and speech path network construction is freed from random access memory speed limit. Other VTDS features: (1) input multiplicity is one; (2) channel graph is serial‐parallel type; and (3) it eliminates highway (space) switches.

Design of time division switching networks considering amount of control

AbstractThe amount of network control as well as the traffic efficiency should be considered in designing a network satisfying the overall economy of the switching system. If high‐speed PCM is adopted, T‐S‐T networks are preferable from the traffic efficiency viewpoint. However, S‐T‐S networks can be preferable from the viewpoint of the amount of control. In this paper, a preferable form of S‐T‐S time division networks is derived from the results of the simulation of the network control processes. S‐T‐S type networks are compared with T‐S‐T type networks from the viewpoints of both the traffic efficiency and the amount of control, and it is revealed that S‐T‐S type networks require less control. Finally, a desired network form satisfying the overall economy is clarified in terms of the whole time division networks including both T‐S‐T types and S‐T‐S types.

On pair relationships in time-division switching network

On pair relationships in time-division switching network

Development of a Time-Division Switching Network Usable in a Very Large Range of Capacities

Well adapted to medium size systems, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</tex> switching networks fully proved the operational value of the time division principles. For higher capacities, the more usual realizations are now STS and mainly TST networks. These are attractive as the growth of the equipment proportional to the square of the number of subscribers is limited to the intermediate stage (or stages). Drastic improvements in semiconductor technology, particularly in the memory field, allow another step: mixing in the same I.C. can, the <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</tex> stages. In this concept, staggering or even functional discrimination of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">T</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</tex> appears to be useless and artificial. The resulting matrix circuit has quite symmetrical input-outputs and the multiple incoming bit positions are distributed to the output in whatever time and space arrangement that is needed. This paper describes the networks based on this concept.

Analysis and Simulation of No. 4 ESS Network Performance

No. 4 ESS is a newly developed, high capacity toll switching machine with a maximum of 107,000 4-wire terminations. Call switching is accomplished via a large digital time-division switching network. The network was evaluated both by a full scale simulation study and by analytical methods to determine its performance characteristics, that is, its blocking and switching capacity. In both simulation and analysis the network was modeled in its real environment, accounting for the effects of the path-hunt strategy. Results of the two methods are in close agreement. They show that the network can switch 47,000 Erlangs of traffic with a probability of blocking a connection on first trial of 0.005.

No.4 ESS: Peripheral System

The No. 4 ess peripheral system economically performs essential switching and signaling functions. A modern time-division switching network has been developed to meet rapidly growing traffic demands and provide a basis for the all-electronic telecommunications network of the future. Common-channel interoffice signaling (ccis) provides high-speed interprocessor communication via data link. Signal processor units perform routine signaling tasks such as scanning and digit collection, effectively increasing the main processor's capacity. To a greater degree than in previous systems, the vital man-machine interfaces are enhanced with sophisticated interactive capability.

No.4 ESS: Transmission/Switching Interfaces and Toll Terminal Equipment

The digital time-division switching network of No. 4 ess imposes new requirements on the transmission/switching interface, while at the same time presenting opportunities for major improvements and economies. Two new terminals–the Digroup Terminal (dt) and the Voiceband Interface (vif)–perform the interfacing for digital and analog transmission systems, respectively. Access to the switching network itself is via serial pcm links, each accommodating 120 voice-frequency channels. The dt terminates digital facilities and performs the multiplexing/demultiplexing necessary to interface the pcm links at the switch. The vif terminates four-wire, voice-frequency analog trunks and performs analog-to-digital and digital-to-analog conversion and multiplexing/demultiplexing to interface with the switch. Both terminals incorporate extensive maintenance hardware and reconfiguration capability. Unitized Facility Terminals (ufts) are used for a variety of functions–attenuation, signaling conversion, etc.–that must be performed on analog trunks between the basic facility distributing frame on the one side and the vif and signal processor on the other. The use of ufts, a standard switching/transmission interface, and modular equipment arrangements and floor plans result in substantial savings in floor space, cabling, and distributing frame requirements, when compared with traditional switching/transmission systems.

Automatic Intercept System: Peripheral Circuits

The Automatic Intercept System forms intercept announcements from phrases recorded on a magnetic drum by means of a sequence of connections through a time division switching network. Automatic fault recovery and diagnostic maintenance features include a trunk test circuit that enables maintenance programs to look in at the system on trunk pairs and test the autonomous scanner and time division network as well as the trunk and service circuits. The Automatic Intercept System time division switching network, announcement machines, operator positions, trunk and service circuits, and the maintenance strategy for these units are described in this paper.

Switching Networks of Planar Shifting Arrays

An array of shift registers that may operate in two orthogonal directions can be called a planar shifting array. This article shows how two basic building blocks, fashioned from planar shifting arrays, may be interconnected to form a time-division switching network of arbitrary size. The characteristics of magnetic bubble and charge-coupled devices are compatible with the concept of planar arrays, and it is in these emerging technologies that switching networks of planar shifting arrays may become practical.

Time-division switching networks with partial-access pulse shifters performing serial-parallel conversion

Some means of time-slot interchanging is required in a pulse-code-modulation (PCM) transit switching system to satisfy the blocking requirements due to the fact that average trunk loading is high and that the time slots of incoming calls are preassigned at the remote office. This paper presents the use of serial-to-parallel conversion and parallel-to-serial conversion pulse shifters, both having limited time-slot interchange capability at the input and the output of the switching networks, respectively. The features of the system are that the required memory capacity is much smaller than the conventional systems and that serial transmission and parallel switching are possible. The results of optimization through blocking probability evaluation and network cost estimation are also described for networks with one, two, and three gate stages, and with an additional parallel pulse-shifter stage.

New Time Division Switch Units for No. 101 ESS

The No. 101 ESS provides centrex service utilizing stored program common control located in the central office and time-division switching units located on the customer's premises. The 2A and 3A switch units serve a wide range of customers (up to 820 lines) using a PAM time-division switching network with lossless through switching, high return loss, and high crosstalk attenuation. System operation, time-division transmission, logic and control, maintenance features, and physical characteristics of the switch units are described.

Trunking aspects of multistage time-division switching network with time-slot-interchange capability

To realise efficient use of interoffice time-division junctors of a p.c.m. integrated communication system, 4-stage and 5-stage interoffice switching networks are proposed. The blocking probabilities of the network are calculated, and it is shown that the efficiency of interoffice junctors reaches 70% and 85% in the 4- and 5-stage networks, respectively.

Three-stage time-division switching network with pulse-shifting junctor as alternate route

The configuration of a 3-stage time-division switching network which has pulse-shifting junctors as the alternate route as well as direct junctors is proposed. A computer simulation to estimate the blocking probability of the system is performed, and proves the system to be nearly as efficient as the switching network without time-slot mismatch loss.

Three-stage time-division switching network by time-slot-interchange principle

A configuration of an efficient time-division switching network to be adapted to a p.c.m. integrated telephone network is described. The traffic efficiency and blocking probability of the system are compared with those of the conventional network.