CA2122778A1 - Interface arrangement for connecting base stations to a private branch exchange - Google Patents
Interface arrangement for connecting base stations to a private branch exchangeInfo
- Publication number
- CA2122778A1 CA2122778A1 CA002122778A CA2122778A CA2122778A1 CA 2122778 A1 CA2122778 A1 CA 2122778A1 CA 002122778 A CA002122778 A CA 002122778A CA 2122778 A CA2122778 A CA 2122778A CA 2122778 A1 CA2122778 A1 CA 2122778A1
- Authority
- CA
- Canada
- Prior art keywords
- base station
- module
- branch exchange
- interface arrangement
- interface
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W84/00—Network topologies
- H04W84/02—Hierarchically pre-organised networks, e.g. paging networks, cellular networks, WLAN [Wireless Local Area Network] or WLL [Wireless Local Loop]
- H04W84/10—Small scale networks; Flat hierarchical networks
- H04W84/16—WPBX [Wireless Private Branch Exchange]
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q11/00—Selecting arrangements for multiplex systems
- H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
- H04Q11/0428—Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
- H04Q11/0435—Details
- H04Q11/0471—Terminal access circuits
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13034—A/D conversion, code compression/expansion
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13098—Mobile subscriber
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13103—Memory
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13106—Microprocessor, CPU
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13194—Four wire connection, transmission
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13209—ISDN
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13214—Clock signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/1322—PBX
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13292—Time division multiplexing, TDM
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04Q—SELECTING
- H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
- H04Q2213/13299—Bus
Abstract
Abstract of the Disclosure To also offer the possibility of mobile communication to branch exchange installations, it is known to add a switching subsystem or a radio network control unit to the private branch exchange, and to connect it to base stations through which the wireless telephones can access the private branch exchange. The task of the invention is to present an interface arrangement between the private branch exchange and the base station, at low cost for large numbers of existing base stations. To that effect, a microprocessor-controlled interface that maintains the DECT-Standard is offered, which shifts the majority of the functions from the base station to the branch exchange. A particularly cost-effective solution is obtained by making multiple use of component groups and dynamic channel assignment.
Description
212277~
Technical Field The invention concerns an interface arrangement for connecting base stations to a private branch exchange, to which wired and/or wireless terminals can have access.
Back~round of the Inven~
The European Telecommunication Standard Institute ETSI has developed a Digital European Telecommunication Standard DECT-Standard for such systems, whereby wireless termina1s can communicate with the private branch exchange via base stations.
This DECT-Standard is the basis for business communication networks, principally for voice communication, but also to support the requirements of data traff1c. DECT is a radio access process to fixed networks, which permits mobile communication in areas of high traffic density.
It is generally known to connect the base station with the private branch exchange through a switching subsystem or a radio network control unit. Such a solution has the advantage that the mobile part of the system can be retrofitted to existing private branch e~cchanges, and functions, from the private branch exchange point of view, like a number of subscribers who are connected to the private branch exchange by analog or digital line interfaces. However, the considerable circuit engineering cost is adisadvantage. This disadvantage is particularly noticeable in areas of high traffic density, such as for example in an office, where a large number of base stations are used, of which one base station serves a single cell in an environment of very small size cells.
This created the desire to develop a cost-effective private branch e~change for both wireless and wired terminals for the special application of an office environment. Such installations are called WPABX - Wireless Private Area Branch Exchange.
Summary of the Invention The task of the invention is to present an interface arrangement that enables the realization of a low cost base station, while maintaining the DECT-Standard. This task is fulfilled by an interface arrangement for connecting base stations to a private branch e~change to which cordless terminals have access via a radio interface and base stations, characterized in that at least one base station is associated with an interface arrangement, with each base station connected via a line interface to a medium access control module .- , -. -.
- ` . . . . ~ , . . .
Technical Field The invention concerns an interface arrangement for connecting base stations to a private branch exchange, to which wired and/or wireless terminals can have access.
Back~round of the Inven~
The European Telecommunication Standard Institute ETSI has developed a Digital European Telecommunication Standard DECT-Standard for such systems, whereby wireless termina1s can communicate with the private branch exchange via base stations.
This DECT-Standard is the basis for business communication networks, principally for voice communication, but also to support the requirements of data traff1c. DECT is a radio access process to fixed networks, which permits mobile communication in areas of high traffic density.
It is generally known to connect the base station with the private branch exchange through a switching subsystem or a radio network control unit. Such a solution has the advantage that the mobile part of the system can be retrofitted to existing private branch e~cchanges, and functions, from the private branch exchange point of view, like a number of subscribers who are connected to the private branch exchange by analog or digital line interfaces. However, the considerable circuit engineering cost is adisadvantage. This disadvantage is particularly noticeable in areas of high traffic density, such as for example in an office, where a large number of base stations are used, of which one base station serves a single cell in an environment of very small size cells.
This created the desire to develop a cost-effective private branch e~change for both wireless and wired terminals for the special application of an office environment. Such installations are called WPABX - Wireless Private Area Branch Exchange.
Summary of the Invention The task of the invention is to present an interface arrangement that enables the realization of a low cost base station, while maintaining the DECT-Standard. This task is fulfilled by an interface arrangement for connecting base stations to a private branch e~change to which cordless terminals have access via a radio interface and base stations, characterized in that at least one base station is associated with an interface arrangement, with each base station connected via a line interface to a medium access control module .- , -. -.
- ` . . . . ~ , . . .
2-~ 2~778 . .1 a microprocessor with associated memories associated with at least one MAC
module, and that the MAC modules are connected jointly via a module for converting adaptive differential pulse code modulation to pulse code modulation and for echo cancellation to a system interface circuit which is connected by a system bus to the central processing unit of the private branch exchange.
The interface arrangement, briefly called DECT-interface, is an integral component of the wireless private branch exchange, and is connected to it by a special private branch exchange-system interface. Concentrating the functions of the DECT-interface and the base station in the DECT-interface, and the multiple use of several groups of components of the DECT-interface circuit and the private branch exchange, renders the construction of the base stations, which are available in large numbers, particularly simple and cost-effective. The low power consumption of the base station is a particular advantage with remote-supply.
Brief Descri~ion of the Drawings The invention will now be explained by means of a configuMtion example. In the pertinent drawings:
Figure 1 is a configuration of a wireless private branch exchange, and Figure 2 is a block circuit diagram of an interface arrangement.
Best M[ode for Carryin~ Ou~ the Invention According to figure 1, a wireless private branch exchange WPABX essentially consists of a central unit CPU, which manages different interfaces through a system bus.
The wireless private branch exchange WPABX can be used as an autonomous installation for connecting wired and/or wireless terminals. However, it is also possible to connect the installation to existing networks. Connection to a Public Switched TelephoneNetwork PSTN is possible through the interface for analog exchange lines, and the connection to an Integrated Service Digital Network ISDN can take place through the To~
interface.
The base stations BS are connected to the DECT-interface through a four-wire line. Each base station supplies one radio station where it provides the radio link for wireless telephones. Each base station BS consists of a transmitter/receiver and a - . - .
, .
21~2778 transmission circuit, which is connected to the DECT-interface. The base station is controlled, synchronized and remote-supplied through the transmission interface lines.
Figure 2 depicts the interface arrangement according to the invention. ln the present example, two base stations are connected to the interface arrangement. For each 5 base station, the interface arrangement contains a line interface BS for connecting a wireless private branch exchange WPABX and a base station BS, a transmission module and a Medium Access Control Module "MAC-module", and a microprocessor with pertinent storage, a module for ADPCM and echo suppression, a system interface and a clock module, in common with the connected base stations BS.
Before calls can be made or received, the wireless telephone must receive information about the environment in which it operates, to decide whether the system can be accessed. To synchronize the wireless telephones with the wireless private branch exchange WPABX, a radio channel is always active in the base station BS, through which system information and the base station BS identification can be emitted. This permits 15 every wireless telephone to recognize in which supply range it operates at the moment.
In the idle position, the wireless telephone only answers to the base station BS with the largest field strength. After logging on to the wireless private branch exchange WPABX, it is decided which channel is best suited for the existing communication connection. In general, this is the channel with the least interference. A quick and interruption-free 20 channel change is required when the subscriber changes location within a cell supplied by a base station, or when moving from one cell to another. This requirement is fulfilled by multiple use within the time multiplex system and a dynamic channel selection. Achannel change takes place when another base station BS in the same series of cells emits a stronger signal than the actual station, or when another channel within the same cell 25 appears to be better suited.
The MAC-module essentially performs the functions defined in the second of the four protocol layers of the DECT-Standard. This includes the selection of physical channels and the set-up and removal of the connections in these channels.
Physical channels are created by joining time slots and the carrier modulated by30 the data rate, which is selected from a spectrum of ten carrier frequencies.
Each base station assigned to a Mac-module consists of a transmitter/receiver, which can utilize each of ten carrier frequencies established in the DECT-Standard, thus _. . ... . . . .
enabling the operation of all 12 duplex time slots, which are established inside a 10 ms frame, while each time slot can opeMte independently at any of the ten carrier frequencies.
Basically, twelve time slots are provided for the direction of transmission from5 the base station BS to the handset, and the same number in the opposite direction of transmission. However, it is also possible to make an asymmetrical arrangement, for example when data are transmitted in one direction and only acknowledgement signals in the other.
Two MAC-modules are managed by one microprocessor, so that the number of 10 channels per base station is adapted according to the need of channels requested from one cell by the so-called dynamic assignment of the channels. A module for converting the adaptive difference pulse code modulation into pulse code modulation, and the elimination of the near and far echo, is also provided for two MAC-modules.
The output capacity of the transmission interface between interface arrangement IS and base station BS is monitored by an Application-Specific Integrated Circuit ASIC by means of time control signa1s and error recovery.
The interface arrangement contains a clock module, which generates a high1y accurate reference pulse, to which the system pulse is synchronized if no external synchronization takes place, for example from an ISDN. The system pulse is used by the 20 clock module to keep all interface arrangements synchronized with the frames and multiframes. However, the reference pulse of the clock module is not active when the synchronization is performed by an external pulse, which for example is supplied by an ISDN.
module, and that the MAC modules are connected jointly via a module for converting adaptive differential pulse code modulation to pulse code modulation and for echo cancellation to a system interface circuit which is connected by a system bus to the central processing unit of the private branch exchange.
The interface arrangement, briefly called DECT-interface, is an integral component of the wireless private branch exchange, and is connected to it by a special private branch exchange-system interface. Concentrating the functions of the DECT-interface and the base station in the DECT-interface, and the multiple use of several groups of components of the DECT-interface circuit and the private branch exchange, renders the construction of the base stations, which are available in large numbers, particularly simple and cost-effective. The low power consumption of the base station is a particular advantage with remote-supply.
Brief Descri~ion of the Drawings The invention will now be explained by means of a configuMtion example. In the pertinent drawings:
Figure 1 is a configuration of a wireless private branch exchange, and Figure 2 is a block circuit diagram of an interface arrangement.
Best M[ode for Carryin~ Ou~ the Invention According to figure 1, a wireless private branch exchange WPABX essentially consists of a central unit CPU, which manages different interfaces through a system bus.
The wireless private branch exchange WPABX can be used as an autonomous installation for connecting wired and/or wireless terminals. However, it is also possible to connect the installation to existing networks. Connection to a Public Switched TelephoneNetwork PSTN is possible through the interface for analog exchange lines, and the connection to an Integrated Service Digital Network ISDN can take place through the To~
interface.
The base stations BS are connected to the DECT-interface through a four-wire line. Each base station supplies one radio station where it provides the radio link for wireless telephones. Each base station BS consists of a transmitter/receiver and a - . - .
, .
21~2778 transmission circuit, which is connected to the DECT-interface. The base station is controlled, synchronized and remote-supplied through the transmission interface lines.
Figure 2 depicts the interface arrangement according to the invention. ln the present example, two base stations are connected to the interface arrangement. For each 5 base station, the interface arrangement contains a line interface BS for connecting a wireless private branch exchange WPABX and a base station BS, a transmission module and a Medium Access Control Module "MAC-module", and a microprocessor with pertinent storage, a module for ADPCM and echo suppression, a system interface and a clock module, in common with the connected base stations BS.
Before calls can be made or received, the wireless telephone must receive information about the environment in which it operates, to decide whether the system can be accessed. To synchronize the wireless telephones with the wireless private branch exchange WPABX, a radio channel is always active in the base station BS, through which system information and the base station BS identification can be emitted. This permits 15 every wireless telephone to recognize in which supply range it operates at the moment.
In the idle position, the wireless telephone only answers to the base station BS with the largest field strength. After logging on to the wireless private branch exchange WPABX, it is decided which channel is best suited for the existing communication connection. In general, this is the channel with the least interference. A quick and interruption-free 20 channel change is required when the subscriber changes location within a cell supplied by a base station, or when moving from one cell to another. This requirement is fulfilled by multiple use within the time multiplex system and a dynamic channel selection. Achannel change takes place when another base station BS in the same series of cells emits a stronger signal than the actual station, or when another channel within the same cell 25 appears to be better suited.
The MAC-module essentially performs the functions defined in the second of the four protocol layers of the DECT-Standard. This includes the selection of physical channels and the set-up and removal of the connections in these channels.
Physical channels are created by joining time slots and the carrier modulated by30 the data rate, which is selected from a spectrum of ten carrier frequencies.
Each base station assigned to a Mac-module consists of a transmitter/receiver, which can utilize each of ten carrier frequencies established in the DECT-Standard, thus _. . ... . . . .
enabling the operation of all 12 duplex time slots, which are established inside a 10 ms frame, while each time slot can opeMte independently at any of the ten carrier frequencies.
Basically, twelve time slots are provided for the direction of transmission from5 the base station BS to the handset, and the same number in the opposite direction of transmission. However, it is also possible to make an asymmetrical arrangement, for example when data are transmitted in one direction and only acknowledgement signals in the other.
Two MAC-modules are managed by one microprocessor, so that the number of 10 channels per base station is adapted according to the need of channels requested from one cell by the so-called dynamic assignment of the channels. A module for converting the adaptive difference pulse code modulation into pulse code modulation, and the elimination of the near and far echo, is also provided for two MAC-modules.
The output capacity of the transmission interface between interface arrangement IS and base station BS is monitored by an Application-Specific Integrated Circuit ASIC by means of time control signa1s and error recovery.
The interface arrangement contains a clock module, which generates a high1y accurate reference pulse, to which the system pulse is synchronized if no external synchronization takes place, for example from an ISDN. The system pulse is used by the 20 clock module to keep all interface arrangements synchronized with the frames and multiframes. However, the reference pulse of the clock module is not active when the synchronization is performed by an external pulse, which for example is supplied by an ISDN.
Claims (5)
1. An interface arrangement for connecting base stations (BS) to a private branch exchange (WPABX) to which cordless terminals have access via a radio interface and base stations (BS), characterized in that at least one base station (BS) is associated with an interface arrangement, with each base station (BS) connected via a line interface to a medium access control module (MAC module) and a microprocessor with associated memories (RAM, EPROM) associated with at least one MAC module, and that the MAC
modules are connected jointly via a module for converting adaptive differential pulse code modulation to pulse code modulation and for echo cancellation to a system interface circuit which is connected by a system bus to the central processing unit (CPU) of the private branch exchange (WPABX).
modules are connected jointly via a module for converting adaptive differential pulse code modulation to pulse code modulation and for echo cancellation to a system interface circuit which is connected by a system bus to the central processing unit (CPU) of the private branch exchange (WPABX).
2. An interface arrangement as claimed in claim 1, characterized in that the base station (BS) is connected by a four-wire line to a module containing a protective device and a feed circuit, and that this module is connected to the MAC module via a transmission module electrically isolated from it.
3. An interface arrangement as claimed in claim 1, characterized in that the MAC module has means for selecting the physical channels between the cordless terminal and the base station, establishes and releases the connections on said channels, and multiplexes and demultiplexes the control information with information from higher-level protocol layers and with error information, and that the seamless channel change within a cell served by a base station (BS) or when moving from one cell to another is managed by the respective MAC module associated with the base station (BS).
4. An interface arrangement as claimed in claim 1, characterized in that one MAC module, the so-called master MAC module, has means for synchronizing all other MAC modules of the interface arrangement.
5. An interface arrangement as claimed in claim 1, further having means wherein the modules for converting adaptive differential pulse code modulation to pulse code modulation and for echo cancellation, which are present during voice transmission, are bypassed during data transmission.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4315621A DE4315621A1 (en) | 1993-05-11 | 1993-05-11 | Interface arrangement for connecting base stations to a private branch exchange |
| DEP4315621.5 | 1993-05-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2122778A1 true CA2122778A1 (en) | 1994-11-12 |
Family
ID=6487753
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002122778A Abandoned CA2122778A1 (en) | 1993-05-11 | 1994-05-03 | Interface arrangement for connecting base stations to a private branch exchange |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US5799250A (en) |
| EP (1) | EP0624995A1 (en) |
| JP (1) | JPH0775151A (en) |
| CA (1) | CA2122778A1 (en) |
| DE (1) | DE4315621A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5757902A (en) * | 1995-01-27 | 1998-05-26 | Matsushita Electric Industrial Co., Ltd. | Telephone exchange for wire telephone and radio telephone |
| US6360245B1 (en) | 1996-05-15 | 2002-03-19 | Siemens Schweiz Ag | Computerized communication system for voice and data services |
Families Citing this family (37)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2102956B1 (en) * | 1994-07-27 | 1998-04-01 | Alcatel Standard Electrica | DUAL FIXED-MOBILE COMMUNICATIONS SYSTEM. |
| EP0800749B1 (en) * | 1994-12-30 | 2003-06-11 | Telefonaktiebolaget Lm Ericsson | System and method relating to cellular communications |
| US5734699A (en) * | 1995-05-04 | 1998-03-31 | Interwave Communications International, Ltd. | Cellular private branch exchanges |
| EP0829172B1 (en) | 1995-05-31 | 1999-09-22 | Siemens Aktiengesellschaft | Cellular cordless telecommunication system with isdn connection |
| DE29513273U1 (en) * | 1995-08-18 | 1997-01-02 | Dfg Deutsche Fernsprecher Gmbh | Connection device for analog subscriber devices on mobile radio networks |
| US5978369A (en) * | 1995-09-08 | 1999-11-02 | Vlsi Technology, Inc. | Efficient generation within a remote base station of a synchronization signal for a cordless communication system |
| DE19536530C1 (en) * | 1995-09-29 | 1996-11-28 | Siemens Ag | Cordless telecommunication system with secure inter-operability of cordless telecommunication applications |
| DE19543841C1 (en) * | 1995-11-23 | 1996-12-05 | Siemens Ag | Transmission system for DECT standard applications |
| DE19547020C1 (en) * | 1995-12-15 | 1996-12-12 | Siemens Ag | Mobile radio communications subscriber network |
| DE19547110A1 (en) * | 1995-12-16 | 1997-06-19 | Sel Alcatel Ag | Mobile radio system with wired subscriber lines |
| KR0162839B1 (en) * | 1996-01-22 | 1998-12-01 | 김광호 | Pbx wireless phone system for dect terminals |
| DE19616239C2 (en) * | 1996-04-15 | 2001-04-19 | Deutsche Telephonwerk Kabel | Method for connecting base stations of a cordless communication system to an ISDN private branch exchange |
| DE19615563C2 (en) * | 1996-04-19 | 1998-07-23 | Nokia Mobile Phones Ltd | Method for operating a telecommunications system and telecommunications system in which the method can be used |
| DE19618243A1 (en) * | 1996-05-07 | 1997-11-13 | Sel Alcatel Ag | Arrangement for operating a mobile terminal in a radio switching system with different transmission standards |
| DE19625814A1 (en) * | 1996-06-28 | 1998-01-02 | Sel Alcatel Ag | Cellular radio system |
| IT1284784B1 (en) * | 1996-09-09 | 1998-05-21 | Olivetti Telemedia Spa | MULTIPROTOCOL SYSTEM AND DEVICE FOR THE EXCHANGE OF INFORMATION. |
| KR19980051651A (en) * | 1996-12-23 | 1998-09-25 | 김광호 | Connection between modem and public telephone line |
| EP0863684A3 (en) * | 1997-03-03 | 2000-05-17 | Victor Company Of Japan, Ltd. | Communication system |
| KR100258148B1 (en) * | 1997-03-28 | 2000-06-01 | 윤종용 | Method of, inter-cell bearer handover in dect wireless pabx |
| US6223055B1 (en) * | 1997-10-24 | 2001-04-24 | Lucent Technologies, Inc. | Wireless office architecture and method of operation thereof |
| US5995849A (en) * | 1997-11-26 | 1999-11-30 | Direct Wireless Communication Corp. | Direct wireless communication system and method of operation |
| AT407813B (en) * | 1997-12-18 | 2001-06-25 | Ericsson Austria Ag | TELEPHONE SYSTEM |
| AT406994B (en) * | 1998-04-20 | 2000-11-27 | Siemens Ag Oesterreich | METHOD FOR CONTROLLING THE BASE STATION OF A RADIO TELEPHONE SYSTEM AND BASE STATION OF A RADIO TELEPHONE SYSTEM |
| AT411121B (en) * | 1998-04-20 | 2003-09-25 | Siemens Ag Oesterreich | METHOD FOR CONTROLLING A DIGITAL SYSTEM |
| KR100377342B1 (en) * | 1998-09-28 | 2003-05-17 | 엘지전자 주식회사 | Wired / wireless connection device of key phone system |
| KR100582568B1 (en) * | 1999-08-25 | 2006-05-23 | 삼성전자주식회사 | Synchronization control apparatus of the DECT system |
| US7260078B1 (en) | 2000-02-08 | 2007-08-21 | Siemens Aktiengesellschaft | Method and system for providing management protocol mediation in wireless communications networks |
| US6591114B1 (en) | 2000-02-24 | 2003-07-08 | Qualicom Systems, Inc. | Fixed cellular communications system |
| US6944150B1 (en) * | 2000-02-28 | 2005-09-13 | Sprint Communications Company L.P. | Method and system for providing services in communications networks |
| US6970719B1 (en) | 2000-06-15 | 2005-11-29 | Sprint Spectrum L.P. | Private wireless network integrated with public wireless network |
| US7039025B1 (en) | 2000-09-29 | 2006-05-02 | Siemens Communications, Inc. | System and method for providing general packet radio services in a private wireless network |
| USH2079H1 (en) | 2000-09-29 | 2003-09-02 | Opuswave Networks, Inc. | Packet-based wireless local loop and method |
| SE518470C2 (en) * | 2001-02-12 | 2002-10-15 | Ericsson Telefon Ab L M | Controller for a subsystem in a base station for mobile telephony |
| US20020181691A1 (en) * | 2001-05-22 | 2002-12-05 | Teltone Corporation | PBX remote telephone control system |
| KR20030030369A (en) * | 2001-10-10 | 2003-04-18 | 서두인칩 주식회사 | A bus apparatus for a base station modem chipsets |
| KR100475179B1 (en) * | 2002-11-12 | 2005-03-11 | 엘지전자 주식회사 | Method for calling in wireless terminal of key phone system and method thereof |
| KR20060078044A (en) * | 2004-12-30 | 2006-07-05 | 엘지노텔 주식회사 | Method for call transfer when out-of-range of terminal in dect wireless communication |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4128811A1 (en) * | 1991-08-30 | 1993-03-04 | Standard Elektrik Lorenz Ag | EXTENSION SYSTEM |
| JPH06165242A (en) * | 1992-10-26 | 1994-06-10 | Philips Electron Nv | Communication system |
-
1993
- 1993-05-11 DE DE4315621A patent/DE4315621A1/en not_active Withdrawn
-
1994
- 1994-05-03 CA CA002122778A patent/CA2122778A1/en not_active Abandoned
- 1994-05-06 EP EP94107117A patent/EP0624995A1/en not_active Withdrawn
- 1994-05-11 JP JP6097725A patent/JPH0775151A/en active Pending
-
1996
- 1996-03-22 US US08/621,206 patent/US5799250A/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5757902A (en) * | 1995-01-27 | 1998-05-26 | Matsushita Electric Industrial Co., Ltd. | Telephone exchange for wire telephone and radio telephone |
| US6360245B1 (en) | 1996-05-15 | 2002-03-19 | Siemens Schweiz Ag | Computerized communication system for voice and data services |
Also Published As
| Publication number | Publication date |
|---|---|
| DE4315621A1 (en) | 1994-11-17 |
| EP0624995A1 (en) | 1994-11-17 |
| US5799250A (en) | 1998-08-25 |
| JPH0775151A (en) | 1995-03-17 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued | ||
| FZDE | Discontinued |
Effective date: 20030505 |