RU123273U1 - DEVICE FOR MODERNIZATION OF AUTOMATIC TELEPHONE STATION - Google Patents

Abstract

1. A device for upgrading an automatic telephone exchange of a coordinate type in the form of a module installed on existing equipment, characterized in that the module contains digital-to-analog conversion units and an additional unit consisting of a serially installed protocol converter (M-ITG), two pairs of control modules ( MKD) connected to the Internet switches, and the OMS maintenance module connected to both switches. 2. The device according to claim 1, characterized in that the digital-to-analog conversion units are installed on the operating equipment of the automatic telephone exchange in the incoming cord set between the signal receiving and processing units and the unit for interaction with the subscriber search stage, and in the outgoing cord set between the receiving and processing units for incoming and processing of outgoing signals of digital-to-analog conversion units. 3. The device according to claim 1, characterized in that the additional unit is installed on the existing equipment of the automatic telephone exchange between the cord sets, which additionally include a digital-to-analog conversion unit, and the Internet protocols of the multiservice network. The device according to claim 1, characterized in that the control modules of the additional unit are preprogrammed to switch to a closed 10-digit numbering plan.

Description

The utility model relates to telecommunications, namely to telephone communications, in particular, to devices for the modernization of automatic telephone exchanges (ATS).

In connection with the adoption of Order No. 142 of December 8, 2006 by the Ministry of Telecom and Mass Media of the Russian Federation, the Russian Federation is organizing a transition to a closed numbering plan when establishing intra-zone telephone connections and excluding from the numbering plans of local telephone networks telephone numbers with the first digit equal to “1 ". Moreover, the subscriber number must consist of ten characters. The full international number of the called party may have 11-12 characters.

Currently, urban telephone networks use an open numbering plan with permanent codes. With an open numbering plan, the number of the calling subscriber depends on the type of connection - local, area or long distance. The long-distance number of the subscriber on the country's network contains ten digits and has the structure ABCabxxxxx, where ABC is the permanent three-digit area code, ab is the code of the local network or one hundred thousandth group of subscribers, and the last five digits xxxxx are the five-digit subscriber number. In accordance with the adopted zonal numbering principle, the entire territory of the country is divided into 166 telephone zones with a single seven-digit numbering of subscribers. With automatic long-distance communication, the subscriber first dials the established (unified in Russia) index of access to the automatic telephone exchange (Automatic Long-Distance Telephone Station) - number 8, then the area code of the ABC and then seven digits of the zone subscriber number. When calling the subscribers of the GTS (City Telephone Network) of the regional center with five-digit or six-digit local numbering, the local number of the subscriber should be supplemented with the zone (seven-digit) numbers 22 or 2. respectively. When calling the subscribers of the GTS of the regional center where the zone is not organized (no automatic telephone exchange), it is allowed to supplement the local subscriber number with zeros to the zone number.

At the moment, all values except 1 and 2 can be used as the number “A”, and any numbers as “B” and “C”. The first digit of the subscriber number cannot be 8 and 0 with seven-six-five-digit numbering. During intra-zone communication, instead of ABC, the number 2 is dialed (i.e. 82 ab xxxxx), which is an intra-area code. Digits other than 8 and 0 can be used as “a”, and any digits as “b” (Marder N.S. Numbering in the public telecommunication networks of the Russian Federation. - M .: IRIAS, 2004, p.95- 144).

Numbering is called closed (unified) if the subscriber is called by dialing the same number regardless of the location of the calling point. Thus, with closed numbering, the number of the calling subscriber does not depend on the type of communication - local, zone or long-distance. At the same time, in order to transfer urban telephone networks to 10-digit closed numbering, it is necessary to reconstruct coordinate automatic telephone exchanges (ATSK), which usually support these telephone networks.

ATSK mainly contains a subscriber kit, a contact field with markers, as well as outgoing and incoming cord sets (ISHK and VSHK). The contact field of existing ATSKs consists of groups of relay-type contact springs with short-circuit contacts — multiple coordinate connectors (MKS), and switching devices are controlled using station registers and markers. The choice of direction and the search for a free line is carried out by a marker that controls the communication device, which contains the caller of the calling input, the determinant of the desired direction of communication, the device that marks the free intermediate lines for connection, the test device, the switching device and the control device (B.S. Goldshtein Switching Systems 2nd ed., Revised and additional St. Petersburg: BHV - St. Petersburg, 2004, p. 63-77).

ATSK works as follows. When removing the microphone from the telephone to the telephone exchange in the subscriber set (AK), it draws the linear relay arm (L) and sends a request (signal) to the subscriber search stage of links A and B (MAI AV) to connect the outgoing cord set (ISK) to the calling line subscriber. At this request, the MAI AV marker determines the caller’s line (the caller’s line number is marked in the marker by triggering the corresponding decimal relays and unit relays), selects a free intermediate path between the ISS (multiple coordinate connector) links A and B and ISK. which has at least one subscriber register (ARB), as well as a free search marker (MRI) and a group search marker (MGI).

After determining the free HMI, the MAI AB marker includes the A and B links that select and hold the electromagnets of the ISS, so that the HMI is connected to the caller’s line. At the same time, in the subscriber kit, the isolation relay (P) attracts the anchor. Then the MAI AV marker is turned off, and the ISK sends a request to MRI to connect the ARB register. MRI determines the HMI waiting for the register to be connected, searches for a free register and turns on the corresponding select and hold magnets of the ISS RI, through the field of which the register is connected to the HMI. Then MRI is turned off. Having received the station response signal from the register, the subscriber proceeds to dial the number, all of which are recorded in the register. The connection is controlled by tokens, which for this purpose request a register about the dialed number. The exchange of information between the register and markers is carried out by the frequency method according to the “shuttle” method (B.S. Goldshtein Switching Systems. 2nd ed., Revised and additional St. Petersburg: BHV - St. Petersburg, 2004, p. 63-77).

The disadvantage of the existing method of organizing the numbering of urban telephone networks in ATSK is the impossibility of providing 10-digit numbering, which becomes necessary for large cities, primarily for Moscow, and the direct switching of ATSK to 10-digit numbering without modernization of ATSK is impossible due to a fundamental limitation of register - ATSK marker equipment with a total of 7 digits.

For the modernization of existing ATSKs, the introduction of additional devices to expand their functional capabilities is currently being used.

In particular, it is known a device for modernization of existing ATSK, which allows you to equip it with a time-based system for recording and measuring the duration of all outgoing telephone connections of subscribers, adopted by the authors for the closest analogue. The device is a hardware-software three-level system controlled by computers, installed between the marker and the HSC and connected to the wires of the AD marker and the wires of the TP ISHK, [RU 88233, 2009].

The disadvantage of this device is the inability to use it to transfer the PBX to a closed numbering plan.

The problem solved by the authors was to create a device capable of modifying existing ATSC, allowing them to combine the dialing and processing of 10-digit numbering with new additional types of services.

This problem was solved by creating a device that is a module containing digital-to-analog conversion (BCA) units and an additional unit (DB) consisting of sequentially installed protocol converter (M-ITG), two pairs of control modules (MKD) connected to Internet switches, and an OMS maintenance module associated with both switches.

During modernization, ATSK BCA is installed on cord sets — in the incoming cord set between the signal receiving and processing units and the interaction unit with the subscriber search stage, in the outgoing cord set between the receiving and processing blocks for incoming and outgoing signal processing, and the DBs are connected to the Internet protocols of the multiservice network and cord sets.

To connect to the Internet Protocol (IP network), the DB uses two Internet interfaces, each of which belongs to one of two control modules operating in load sharing mode. It communicates with external devices through an IP network using SIP signaling protocols. Voice information over an IP network is transmitted using Real Time Protocol (RTP). For communication with the IMS core and signaling exchanges, the standard UDP port 5060 is usually used. However, when interacting with the IP network, the DB does not allocate separate bundles of channels for various types of traffic. There is a single bundle of IP channels for inbound, outbound, intra-office traffic. At the output of the software module (actually, at the output of the coordinate exchange), speech is transmitted in the form of a stream of IP packets.

Signaling procedures are defined by the SIP protocol specifications. This protocol is used for the exchange of information between all DBs and the IMS core included in the NGN (Next Generation Network) segment. When providing the main service, the IMS core does not process voice traffic.

Using this device allows the IMS core to transmit 10 characters of a number to maintain a closed numbering plan throughout the network.

To ensure incoming and outgoing communication of remote subscribers, the DB is connected to the outputs of the coordinate substation via two-wire interfaces, which saves on laying subscriber lines, and at the same time makes it possible to process 10 characters for incoming and outgoing calls to the subscriber.

To ensure the connection of institutional or city exchanges to ATSK stations with a modified circuit, it is connected to the PCM (Pulse Code Modulation) of these exchanges that performs the functions of analog-to-digital / digital-to-analog conversions (ADC / DAC), E1 paths, the number of which depends on the number of three-wire connecting lines.

The essence of the proposed solution is illustrated by the following schemes and figures.

Figure 1 presents the installation diagram of the device in ATSK. Figure 2 presents a diagram of the DB, figure 3 and 4 shows a diagram of the installation of the ACB in the HSC and HIS. Figures 5 and 6 show signaling exchange scenarios (outgoing and incoming calls).

In this case, the following notation is used in the figures and diagrams: AK - subscriber set; MAI - subscriber search stage marker; VShK - incoming cord kit; IShK - outgoing cord set; MRI - a register search marker; RI search register; GI group finder; IMS - fragment of the next generation multiservice network (NGN); SIP - session initiation protocol; RTP - real-time protocol; M-ITG - protocol converter; M-ISHK - modified outgoing cord kit; M-VSHK - modified incoming cord kit; AI - subscriber seeker; PS - companions; BOI - signal processing unit of the 8-wire interface; BACP - block of analog-to-digital conversion; BPOI - signal reception and processing unit of the 8-wire interface; BOS - signal processing unit for interface with M-ITG; BPOS - signal reception and processing unit for the interface with M-ITG; BAI - unit of interaction with the subscriber search stage.

DB consists of the gateway equipment of the protocol converter (gateway) M-ITG and equipment M-Core.

The objective of M-ITG is to ensure interaction with the upgraded telephone exchange using 10-digit numbering. In this case, M-ITG performs the following functions:

- organization of incoming calls to subscribers of the modernized PBX with the ability to process more than 10 digits of the number;

- organization of in-house calls;

- organization of calls within the same building;

- organization of calls within the "former" analog network segment;

- one M-ITG module supports up to 4 E1 paths;

- interaction with the upgraded automatic telephone exchange along the E1 paths with signaling 2 VSK ("pulse shuttle");

- interaction with the automatic caller ID (AON) equipment: collecting and determining the number of the calling subscriber;

- providing voice information over an IP network with SIP signaling;

- supports codecs: G.711, G.729 for transmitting voice information;

- supports the T.38 protocol for transmitting facsimile information;

M-ITG also uses the Fast Internet (100Base-T) interface to communicate with the IP network.

The M-ITG software has the necessary system for diagnosing, preventing and automatically correcting emergency situations. Monitoring and management of M-ITG is carried out from a workstation (AWS). Access to the M-ITG is via a shared local data network.

The M-Core equipment consists of two control modules connected to the Internet switches, (MCD), containing the software subsystem M-IVR-L or another similar software product, and a maintenance module (OMS), connected to both Internet switches.

MKD performs the functions of a software switch: it provides call routing, management of M-ITG gateway equipment, provision and accounting of telecommunication and intellectual services, while supporting a closed plan for numbering and processing a 10-digit subscriber number. MKD routes the call to the 10-digit number of the called subscriber; by 10-digit caller's number; by a combination of the called number and the calling number; by subscriber category; by the prefix of the telecommunications operator.

The MKD software subsystem M-IVR-L provides access to communication services for communication network subscribers (generates accurate time information, interacts interactively with the subscriber).

MKD is controlled from an automated workstation (AWP). Access to MKD occurs through the local Internet.

The OMS module is a maintenance server for all MPN elements. It is a repository of CDR records and debug logs of all modules.

In the MPN OMS system performs the following functions:

- collection of information on the health of MPN elements;

- collecting information about the stages of establishing connections

- collection and reporting of statistical data:

- management of subscriber profiles, in particular, setting a subscriber category;

- blocking outgoing communication;

- management of services available to the subscriber;

- quality control of the established conversational connection;

- tracking of voice and signal exchanges between MPN modules;

OMS is connected to all modules M-ISHK-40, M - ITG, MKD via a closed protocol. OMS connects to Internet switches via SNMP.

To increase the stability of the DB in the M-Core provides backup system support. The modules operate in load sharing mode, when one of the modules fails, the remaining modules begin to service the entire load. Switching to the reserve occurs without increasing the likelihood of loss on calls and other network quality indicators.

M-ISHK and M-VSHK provide replacement of existing cord sets (ISHK and ISHKT) at coordinate exchanges and at coordinate substations. They support interaction with payphones and with PSK-1000 modules via two-wire interfaces.

The software of cord sets supports work with ATSK and ATSKU. The type of station is set in the software, and is configured when installing MPN.

One set of M-ISHK-40 and M-VSHK are installed instead of 40 existing cord sets in the same cabinet, so as to ensure the preservation of inter-static communications and at the same time provide support for 10-digit numbering. Monitoring and control of cord sets is done from the workstation; access is via a local data network.

The DB supports the following call routing criteria: by the number of the called party; by subscriber category; by prefix ODS (operational dispatching service).

The maximum length of a received number is 32 digits. Subscriber number “A” is transmitted completely, which allows you to support any version of a closed numbering plan, including the accepted 10-digit numbering. The DB supports the setting of a substitution prefix, which will be added to the digits of the number issued by the AON equipment. It is possible to change the PBX index.

DB supports changing the accepted digits of a number from a subscriber, in order to comply with the standard for format conversion of numbers built using packet switching technology.

Modified ATSK works as follows. Outgoing calls from the DB are distributed evenly between the addresses of the IMS core. If it is not possible to establish a connection through IP_IMS_1, all calls are automatically routed to IP_IMS_2. If it is not possible to establish a connection through IP_IMS_2, all calls will be automatically routed to IP_IMS_1. The unavailability of the corresponding address is determined by standard means of the SIP protocol: when making a call, an INVITE request is sent and a timer is turned on to wait for a response. If no response is received, the INVITE message is repeated again. The number of re-sendings of the INVITE message before the direction is marked as unavailable is configured in the configuration. If the INVITE messages sent by the DB to the IP_IMS_1 address do not receive a response within the specified time, then this address is marked as unavailable. In this case, the call is not answered, but is automatically routed to the IP_IMS_2 address. The address is marked as unavailable for a certain period of time during which no calls are sent to it. At the end of this period, the unavailability flag is cleared, and the direction again becomes available for sending calls. If the response to INVITE messages does not come again, then the algorithm repeats.

The algorithm is also true for the opposite case, when the IP_IMS_1 address becomes unavailable, and IP_IMS_2 remains in operation.

Incoming calls from the IMS core are distributed between two DB addresses depending on the number of the called subscriber. If the DB serves 10,000 subscribers, then the IMS core routes calls for the first half of the range (5,000 numbers) to IP_MPN_1, while IP_MPN_2 is the backup address. For the second half of the range (5000 numbers), the IMS core routes calls to IP_MPN_2, while IP_MPN_1 is the backup address.

To provide outgoing communication from payphones, the DB is connected via cross equipment directly to payphones via a two-wire interface. To provide incoming communication to subscribers, it connects to the inputs of the CD stage using a five-wire interface. The functional purpose of the wires of the five-wire interface is presented in table 1

Table 1 Functionality of the wires of the five-wire interface Name Appointment but Conversation wires for connecting to a telephone b from Lesson confirmation wire d Lesson wire k Readiness

To transfer the address information from the DB to the markers of the CD and AB steps, the multi-frequency code “2 of 6” is used. A typical scenario of signal exchange with outgoing and incoming communication with an analog subscriber is shown in FIGS. 5 and 6.

DB provides the conversion of voice information from analogue exchanges into a form suitable for transmission over IP networks. MPN carries out encoding of information, packaging of voice information in RTP / IP packets, as well as inverse transformation; supports the exchange and conversion of signaling messages both with switching or terminal equipment of analog automatic telephone exchanges, as well as with the IMS core, software switch or terminal device of the IP-telephony network; processes and converts alarm messages of an alarm system using channel switching technology into alarm messages of alarm systems using information packet switching technology, supports different numbering plans (including a closed numbering plan with 10-digit numbers) and provides the use of analog automatic telephone exchanges when using a closed plan numbering, supports changing address information.

Claims (4)

1. A device for upgrading an automatic telephone exchange coordinate type in the form of a module installed on existing equipment, characterized in that the module contains digital-to-analog conversion units and an additional unit consisting of sequentially installed protocol converter (M-ITG), two pairs of control modules ( MKD) associated with the Internet switches, and the OMS maintenance module associated with both switches. 2. The device according to claim 1, characterized in that the digital-to-analog conversion units are installed on the existing equipment of the automatic telephone exchange in the incoming cord set between the signal receiving and processing units and the interaction unit with the subscriber search stage, and in the outgoing cord set between the receiving and processing blocks incoming and outgoing signal processing digital-to-analog conversion blocks. 3. The device according to claim 1, characterized in that the additional unit is installed on the existing equipment of an automatic telephone exchange between cord sets, which additionally include a digital-to-analog conversion unit, and Internet protocols of a multiservice network. 4. The device according to claim 1, characterized in that the control units of the additional unit are pre-programmed to switch to a closed 10-digit numbering plan.