DE19936776A1 - Coupling different trunked radio systems using interfaces connected directly together without going via switching centre - Google Patents

Abstract

The method involves coupling between switching centres of the radio network using interface devices (11,12) which are directly compatible with each other, on the side of the radio system to be coupled. The interface devices are connected directly together without going via a switching centre. The direct connection may be established via a public or private communication network. A PCM transmission system (13) may be used for the direct connection. The interface devices may be analogue or digital interface cards.

Description

The invention relates to a method for coupling different trunked radio systems, according to the generic term of Claim 1.

Analog trunked radio systems are used by different System suppliers manufactured. Therefore, it can be within a new economic region that a service provider here historically two different system technologies are required operates. To the radios in the "other" network anyway To achieve this, transitions must be provided.

The well-known system suppliers provide technologies that none Provide internal interfaces to the networks connect. Only the air interface is standardized and can cross-system from different radio devices be used.

Several attempts have been made in the past to create transitions from one network to another. Has proven to be of good quality and user-friendly Transition via PABX (PBX technology) or PSTN (public Landline). An older variant using two-wire technology and PABX has turned out to be technically too difficult and for the User is found to be too complicated and will not considered further.  

The only standardized interface to the outside world that every manufacturer has in its range is the two-wire a / b interface, which in principle simulates a telephone. A system manufacturer provides cards on an analog basis for dialing in with DTMF (multi-frequency dialing) dialing, for direct dialing or for dialing into the public fixed network. Analog cards are also available from other system manufacturers. In the case of new installations, however, these are replaced by a newly developed ISDN card that is connected directly to the S ₀ bus. A coupling is therefore only possible via these cards. PSTN or PABX connection (private branch exchange) possible.

The object of the invention is a method for coupling various trunked radio system technologies, with which one technical and maintenance simplification of the Interconnection of network elements can be achieved.

The object is achieved by the features of independent claim 1 solved.

The essence of the invention is the use of Interface devices on the part of the to be coupled Trunked radio systems, the common, directly compatible Provide interface protocols so that they can be directly over a corresponding connection can be connected.

The fact that both interface devices on the Use the same protocols on the line side (i.e. work symmetrically) is a PBX mediation superfluous if they do not Has routing functions (routing function).

This is used according to the invention because routing alone determined by an entered selector of the participant  becomes. In terms of transmission technology, there is a direct connection between the most optimal form of connection for the networks to be coupled. The Connection can be part of any public or private communication network with sufficient Transmission capacity.

Advantageous embodiments and further bindings of Invention are the subject of the dependent claims.

The following advantages are achieved with the invention compared to the coupling methods previously used

• - Simplest technical function, simple handshaking, Standard hardware.
• - Direct point-to-point connection, facilitates the Error limitation considerably in the event of a fault. Influences from Transfer networks (T-Net, ISDN) are excluded.
• - Fastest connection setup times, no delays through intermediary communication networks and their Facilities. Now sounds when the subscriber is busy or Ringing tone, this is guaranteed to come from the radio exchange. Technically clean call clearing; recognize analog cards not the busy tone and may remain U. until the timeout (3 min.) hang if the called party does not habitually triggers (is also not necessary for internal calls.
• - The possible error limitation can be concentrated on the respective components. The handshake process is on track the cards or can use the PCM systems simplest means (voltmeter) can be checked. No protocol checks are required in ISDN.
• - Maximum speech quality, since from radio to radio there is always a 4-wire connection. 2- / 4-wire Transitions are fundamentally complicated and level produce unavoidable return effects.

The following is the prior art and the invention based on an embodiment with reference to one drawing figure each described in more detail. Go there from the drawings and their description further features and advantages of the invention. Show it:

Fig. 1: coupling of trunked radio systems according to the prior art;

Fig. 2: coupling of trunked radio systems according to the invention.

Fig. 1 shows a connection of radio exchanges 1, 2 of two trunked radio networks through a public telecommunications network 9 (PSTN) to the present state of the art. This type of coupling can be ignored as too impractical because of the long sequences of digits to be selected for establishing a cross-network connection. Only with the use of ISDN connections can routing be set that simulates a leased line for the radio subscriber.

In order to make the coupling as convenient as possible for the subscriber, the use of suitable interfaces, such as PABX cards 3 , which are assigned to the subscriber, or PID cards 5 , ie ISDN cards, which are also via selectors, is the subscriber assigned, necessary. PSTN cards 4 , 6 are accessible to all participants via a selector. The selection procedure is limited to entering the selector for the desired trunked radio network (several are possible) and a z. B. 4-digit short number, which is also used for PSTN dial-up.

The subscriber thus enters 5 digits and starts the call request. The system technology then occupies the corresponding interface card. In the radio exchange 2 , a number stored in the PID card 5 and assigned to the number sequence is dialed via ISDN based on the number sequence entered. The call is forwarded via the public ISDN network and either reaches an ISDN connection with terminal adapter 7 , 8 of the counter operator or, depending on the number, reaches a conventional direct dialing connection.

In both cases, the short number only reaches the radio exchange 1 of the other trunked radio network after a while (direct dialing = pulse dialing / PABX card only picks up after a second call) and triggers internal processes.

In the opposite case of establishing a connection from exchange 1 to exchange 2 , the operation of the radio is identical. After the PABX card 3 of the radio exchange 1 has been assigned , the preprogrammed terminal adapter 7 dials the ISDN number of the desired network node and transfers the short number to the exchange 2 .

These options are currently available to the participant To reach radio equipment in networks of other technology.

Fig. 2 shows a schematic of the coupling of two trunked radio systems, the invention displays.

The function is symmetrical from both technology platforms of the trunked radio networks to be coupled and is therefore only described in one direction. The interface cards of the radio exchanges 1 , 2 of both trunked radio networks use the same interface protocols and are coupled to one another via a direct connection.

In the radio of the first network, the call request to the other radio network is determined by a selector (1st digit). The following four digits are the destination subscriber's short number. This election information is used for the respective own radio exchange, e.g. B. Radio switch 1 sent. This switches a connection to a free interface card 11 via the internal switching matrix (bundles of different strengths can be configured in each direction). The card 11 is e.g. B. designed as a PABX card and now switches earth potential to the M (Mouth) line. The remote station 12 thus recognizes the connection request on the E (ear) line. The four speed dial digits are then automatically sent as DTMF tones via the 4-wire voice line. After receiving the last tone, the counter card 12 acknowledges earth potential on the M-wire. This indicates that the cross-connection has been established. The set-up switch 1 switches the speech paths through and the receiving switch 2 searches for the radio subscriber on the basis of the speed dial number in connection with a conversion table.

This process corresponds to dialing in from the PSTN network or from PBXs. If one of the conversation partners triggers the connection, the earth potential on the relevant card 11 , 12 on the M-wire is removed.

On the opposite side 12 , 11 , this state is evaluated as an end indicator and all stages involved, including the radio channel, are also activated there.

This triggering process can take place at any time even when the connection is established. If the short number is not valid or the radio does not answer, the operator 2 is thus clearly signaled that this call setup is in vain. The line is immediately available again after this triggering.

The process in the radio exchanges 1 and 2 does not have to be changed. What is new is the simple and fast handshake method via signal wires of the 6-wire interface cards 11 , 12 without additional switching of an intermediate network.

The circuit can be implemented by the fact that today at all radio locations (operator-independent) PCM  Transmission systems with analog interface cards (Telephone channels with signal wire, FEK or Channel switching, KDU) are installed to internal To provide connecting lines. These are standard equipped with 4-wire speech paths and signal wires. Since the Length of a 64 kbit / s current path does not matter for quality playing more, a point of contact between the strangers is sufficient networks to be coupled to switch transitions.  

Drawing legend

1

Switching trunked radio system A

2nd

Switching trunked radio system B

3rd

Interface device PABX

4th

Interface device PSTN

5

Interface device PID

6

Interface device PIA

7

Terminal adapter

8th

Network termination NTBA

9

Telecommunications network

10th

Network termination

11

Interface device PABX

12th

Interface device PABX

13

PCM transmission device

14

Interface device KDU-FEK

Claims (8)

1. A method for coupling different trunked radio systems, the coupling between (transition) exchanges of the trunked radio systems being set up, characterized in that interface devices ( 11 , 12 ) which are directly compatible with one another are used on the part of the trunked radio systems to be coupled, which directly, without detour an exchange to be connected. 2. The method according to claim 1, characterized in that the direct connection via a public or private Communication network is established. 3. The method according to claim 1 or 2, characterized in that the interface devices ( 11 , 12 ) are connected to one another via a connecting line. 4. The method according to claim 3, characterized in that a PCM transmission system ( 13 ) is used for the direct connection. 5. The method according to claim 1 or 2, characterized in that the interface devices ( 11 , 12 ) are connected to one another via a radio interface. 6. The method according to any one of claims 1 to 5, characterized in that analog interface cards are used as interface devices ( 11 , 12 ). 7. The method according to any one of claims 1 to 5, characterized in that digital interface cards are used as interface devices ( 11 , 12 ). 8. The method according to any one of claims 1 to 7, characterized characterized in that the routing between the Trunked radio systems alone through an entered Selector of a participant is determined.