MXPA99008572A - Multi-input wireless phone with echo suppression - Google Patents

Abstract

A method and apparatus for allowing two or more Wireless Local Loop telephone users to communicate simultaneously with each other and a far end user in which earseal and hybrid echo is reduced. The present invention operates within a Wireless Local Loop telephone having a plurality of telephone inputs, one of which is a dedicated handset (16) and at least one other input being a standard analog telephone (18, 20). Two echo cancellers (30, 32) are used within the phone to reduce the echo produced by the impedance mismatch of a 4-to-2 wire hybrid (44) and the dedicated handset (16). A first echo canceller (30) is optimized to remove the earseal echo generated at the dedicated handset (16) while a second echo canceller (32) is optimized to remove the hybrid echo generated at the 4-to-2 wire hybrid (44). The two echo cancellers operate independently such that neither echo canceller need adapt its filter coefficients when a change in the echo channel characteristics occurs, such as when a speaker hangs up or another speaker joins the conversation.

Description

WIRELESS MULTI-INPUT TELEPHONE WITH PE ECO SUPPRESSION BACKGROUND OF THE INVENTION I. Field of the Invention The present invention relates to digital communications. More particularly, the present invention relates to a novel and improved method and apparatus for canceling echo in a Wireless Local Loop telephony system.

II. Description of the Related Art The use of code division multiple access modulation (CDMA) techniques is but one of several techniques to facilitate communications, where a large number of users of the system are present. The use of techniques CDMA in a multiple access communication system is disclosed in U.S. Patent No. 4,901,307 (the '307 patent) entitled 2SPREAD SPECTRUM MULTIPLE ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS ", and in the Patent of United States No. 5,103,459 (the '459 patent) entitled "SYSTEM AND METHOD FOR GENERATING SIGNAL WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM ", both assigned to the assignee of the present invention and incorporated herein by reference.

P1536 / 99MX In the '307 and' 459 patents, a multiple access technique is disclosed wherein a large number of mobile telephone users, each having a transceiver, communicate via satellite repeaters or land base stations (also known as stations). base or cellular sites), using multiple division code access (CDMA) stepped spectrum communication signals. The use of CDMA techniques results in much greater spectral efficiency than can be achieved using other multiple access techniques. Telephone systems based on cable or cable line are the traditional method of providing non-mobile telephone service. Cable-based telephone systems are well suited for this task because they provide high-quality telephone connections at low operating costs and can meet the increasing demand for telephone service by introducing new telephone cables into the existing network. A disadvantage of cable-based telephone systems is the substantial infrastructure and capital needed for their implementation. These requirements can make non-economic cable-based telephone systems to provide telephone service in areas that are remote or less populated or in areas P1536 / 99MX less developed in - where the required capital is not available. The result is that these less populated and less developed areas often lack adequate telephone service. Also, the time needed to put the required infrastructure in place to less desirable cable-based telephone systems in areas where telephone service must be provided quickly. Cellular telephone systems require substantially less capital and infrastructure than cable-based telephone systems and therefore provide a possible alternative for providing primary telephone service in areas where access to cable-based telephone service is adequate. Wireless cellular systems are known as Wireless Local Loop (WLL). In a WLL system the subscriber units are available in different varieties. A subscriber unit is known as an Integrated Subscriber System (ISS), which has the appearance of an ordinary home telephone, except for an antenna that is used for transmission and reception to and from the base station. The ISS unit contains a telephone and a keyboard, with appearance and operation similar to that of an ordinary home telephone. The voice is provided from the integrated phone to the unit P1536 / 99MX ISS base and it is converted into a digital format so that it can be processed in accordance with CDMA techniques, as described in the '307 and' 459 patents mentioned above. Another type of subscriber unit is the Single Subscriber System (SSS - Single Subscriber System) that provides one or more inputs for standard telephone sets. An SSS unit can be used in a house where standard telephone sets are used, with each telephone having the same ESN so that only one call can be placed or received at a time. Users can pick up a second line and actively participate in the conversation, each home user may be able to communicate with the remote speaker as well as each other, similarly to multiple telephone extensions in the house. The echo is a problem that should be addressed to WLL subscriber stations, both ISS and SSS. In an ISS unit, a seal echo is generated in the ISS phone causing the remote speaker to hear an annoying echo of his or her own voice. In an SSS unit, an echo of the impedance uncoupling results in a 4 to 2-wire converter, known as a hybrid, within the SSS unit. The conversion of 4 to 2 cables is necessary so that standard analog telephones can be put in P1536 / 99MX interface for the SSS. For both ISS and SSS systems, the echo problem is solved using a single network echo canceller located inside the ISS or SSS unit. An example of a network echo canceller is set forth in U.S. Patent No. 5,307,405 (the '405 patent) entitled "NETWORK ECHO CANCELLER" assigned to the assignee of the present invention and incorporated herein by reference. In an ISS unit, the echo canceller can be optimized to cancel the listener stagnation echo. In an SSS unit, the echo canceller can be optimized to cancel the hybrid echo. In many situations, it is desirable to combine the characteristics of the ISS telephone with those of the SSS telephone. That is, there is a need to provide a telephone unit that resembles an ISS unit while allowing analog telephones to interface with it. In such a telephone, the echo would need to be reduced in only one way due to the nature of the analog telephone inputs and the dedicated telephone inputs.

SUMMARY OF THE INVENTION The present invention is a method and an apparatus for combining an ISS unit and an SSS unit to allow telephone conferences between two P1536 / 99MX nearby users and a remote user. The combined unit, known as the ISS / SSS unit, also reduces the echo to the remote user that results from the characteristic impedance of the analog telephones and the ISS input. The ISS / SSS unit uses two echo cancellers to reduce the echo signals. Once the echo canceller is optimized to eliminate the sealing echo that results from the ISS phone and the other is optimized to remove the hybrid echo that results from the analog phone inputs. There are several disadvantages to using a dual echo canceler device. First, each echo canceller can be designed specifically to eliminate the particular type of echo it is going to cancel. Second, if an ISS / SSS user hangs up during a conference call, the echo canceller of the remaining channel does not have to re-converge its filter coefficients since each echo canceller operates only on the echo channel characteristics for its respective user . Another advantage of the present invention is the rapid convergence of echo canceller filter because a near silent state is more likely to occur with a single close speaker compared to a multi-user situation. In one embodiment of the present invention, a wireless telephone is exposed that allows two P1536 / 99MX or more users communicate simultaneously with each other and with a distant user, the telephone comprises a dedicated telephone to provide a first telephone entry and at least one interface to receive an analog telephone entry. The present invention is capable of canceling both the listening staked echo and the hybrid echo in a digital telephone system, the system comprises a remote speaker in wireless communication with at least two nearby speakers, nearby speakers use a wireless subscriber unit, the subscriber unit has at least two user interfaces, one interface is a dedicated telephone, and at least one other interface is a standard 2 wire analog telephone, the standard analog telephone connected to the subscriber unit via a hybrid of 4 to 2 cables, where the subscriber unit allows simultaneous communication between the remote speaker, a close first speaker using a telephone dedicated, and a second speaker using the standard analog telephone, the device comprises a first means of echo cancellation located within the subscriber unit to eliminate the stagnant echo of listening generated in the dedicated telephone and a second means to cancel located echo within the subscriber unit to eliminate the hybrid echo generated in the hybrid from 4 to 2 cables.

P1536 / 99MX BRIEF DESCRIPTION OF THE DRAWINGS The features, objects and advantages of the present invention will be more apparent from the detailed description set forth below, when taken in conjunction with the drawings in which like reference numbers are correspondingly identified throughout. time, and where: Figure 1 is a block global diagram of an ISS / SSS unit; Figure 2 is a functional block diagram of the three-way switch, SSS interface, and SSS interface; and Figure 3 is a simplified block diagram of an echo canceller.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention discloses a Local Wireless Loop telephone system, called an ISS / SSS unit, which includes a telephone and a keyboard as a telephone interface, designated here as ISS and other telephone interfaces provided by standard analog telephones connected to the ISS / SSS unit via standard RJ-llx telephones, designated here as SSS. This type of subscriber station can find use in homes and businesses where multiple telephone extensions are desirable. A problem with the ISS / SSS unit is the P1536 / 99MX presence of echo generated by the ISS and SSS interfaces to the remote speaker. For example, in a three-way call between a remote speaker, an ISS speaker and an SSS speaker, an echo signal is generated by the acoustic coupling between the receiving speaker and the microphone in the ISS telephone, while another echo signal results of the impedance decoupling developed in the hybrid of 4 to 2 cables associated with the SSS interface. Throughout the remaining description of the present invention, the term "remote speaker" means the person who is not using the ISS / SSS unit while the term "near speaker" denotes the speaker using the ISS / SSS unit. Figure 1 is a block global diagram of an ISS / SSS Subscriber WLL station, designated as an ISS / SSS unit 2. Near speakers can use either the ISS 16 telephone or the 18 or 20 analog telephone to send and receive calls. The multiple analog telephones can interface with the ISS / SSS unit 2, indicated in Figure 1 including the analog telephone 20. The interface between the ISS 16 telephone and the codeine 14 is a 4-wire interface, while the connections between the subscriber line interface 12 and the analog telephones 18 to 20 are each, 2-wire connections. For purposes of analysis herein, it will be assumed that only the telephone P1536 / 99MX Analog 18 is connected to the 3 ISS / SSS unit. The three-way switch 10 controls communications between the remote speaker and the ISS / SSS speaker (s). If only one speaker is using the ISS / SSS unit 2, communications between that speaker and the remote speaker are routed through the three-way switch 10 either to the ISS 16 telephone or to the analog telephone 18, depending, Of course, which interface the next speaker is using. The three-way switch 10, in the exemplary mode, is configured in the form of a digital processor, such as the ADSP-2181 model of the ADSP-2100 series of digital signal processors manufactured by Analog Devices of Norwood, Massachusetts. It should be understood that other digital signal processors may be programmed to function in accordance with the teachings herein. Alternatively, other implementations of the three-way switch 10 may be configured from discrete processors or in the form of an application-specific integrated circuit. (SO C) . When the ISS 16 telephone is in use, the voice from the nearby speaker is provided to the codec 14 where it is transformed from analog signal to digitized PCM data samples. If no other nearby speaker is using the ISS / SSS 2 unit, the digital samples are placed in P1536 / 99MX route to modem 8, where the PCM samples are decoded into data packets that are modulated using any type of technique, including TDMA, FDMA or CDMA. The modulated data is then supplied to the RF module 6, where they are overconverted into a high frequency signal and then transmitted via the antenna 4 to a remote base station (s), which are not shown. The voice received from the remote user arrives at the antenna 4 as a high frequency signal that has been modulated in accordance with the particular modulation method used. The RF module 6 subconverts the baseband low signal, filters and amplifies the signal, and supplies it to the modem 8 for demodulation. The received data packet is decoded into digital PCM samples in the modem 8 and is supplied to the three-way switch 10 where it is enroute to the codee 14 when only the ISS 16 telephone is being used. The codee 14 accepts the data PCM and converts them into an analog signal, where they are then supplied to the telephone 16 via a four-wire interface. When the analog telephone 18 is in use, the voice from the nearby speaker is supplied from the analog telephone 18 to the subscriber line interface 12 via a two-wire connection. The analog phone 18 contains a hybrid that combines the two-wire microphone signal with the P1536 / 99 X Two wire cable staggered speaker signal to produce a two wire signal for the ISS / SSS 2 unit. The subscriber line interface 12 contains a 4 to 2 wire hybrid converter that converts the signal from two wires of the analog telephone 18 in a 2-wire transmission signal and in a 2-wire reception signal. The Subscriber Line Interface 12 also contains a codec used to transform the analogue analog voice signal into digital PCM samples. The PCM samples are then supplied to the three-way switch 10, where it is en route to the modem 8 where the PCM samples are encoded into data packets that are modulated in accordance with the selected modulation method. The modulated data is then provided to the RF module 6 where it is overconverted and then transmitted via the antenna 4. The received voice is processed in the same way as described above for the ISS case. If only the analog telephone 18 is being used, the demodulated PCM signal from the modem 8 is sent through the three-way switch 10 to the subscriber line interface 12 only. There, the PCM signal is converted into an analog voice signal and then converted into a 2-wire signal by means of the hybrid located within the subscriber line unit 12. The analog voice signal is P1536 / 99MX It then supplies the analog telephone 18. A conference call can be described in which there are at least three speakers conducting a conversation: a remote speaker, a nearby speaker using 16 ISS telephone and a second nearby speaker using analog telephone 18. During a conference call, the three-way switch 10 provides communications between all parties. The ISS speaker will be able to communicate with both the remote speaker and the analog telephone speaker simultaneously. The speaker of the analog telephone will be able to communicate both with the remote speaker and with the ISS speaker, simultaneously. The remote speaker can communicate with both the ISS speaker and the analog telephone speaker simultaneously. An echo signal is produced both by the acoustic coupling in the ISS 16 telephone, and as a result of an impedance decoupling in the subscriber line interface 12. As a result, the remote speaker will hear an annoying echo of his own voice. Figure 2 is a detailed block diagram of the three-way switch 10, the codee 14 and the subscriber line interface 12. The present invention introduces two echo cancellers in the designated three-way switch. The canceller P1536 / 99MX echo (EC1) 30 is used to cancel the stagnant echo from listening to the telephone 16 while the echo canceller (EC2) 32 is used to cancel the hybrid echo created by the hybrid 44. The EC1 is composed of a filter block 34 adapter that is used to estimate the characteristics of the unknown echo channel and the adder 22 that subtracts the estimated echo signal from the nearby voice signal. The EC2 32 operates in a similar manner, and is composed of the adapter filter block 36 and the adder 28. In the exemplary embodiment, the echo cancellers 30 and 32 are supplied in the manner set forth in the aforementioned '405 patent, entitled "NETWORK ECHO CANCELLER". In a conference call, referring again to Figure 2, the voice received from the remote speaker in the form of PCM samples is provided via the modem 8 to the adder 20 and the adder 24. In the adder 20, the speech samples digitized from the analog telephone speaker are added to the remote digitized voice after passing through the delay element 68 and the attenuation element 70. the attenuation element 70 is an optional feature that is used to prevent the speaker's voice analogue is fed back along the return path of the ISS phone. This could occur when the echo canceller 30 has not been P1536 / 99MX fully adapted to the unknown echo channel 46 during the first few seconds of a call. The delay element 78 is a parasitic result of the attenuator 70 and, therefore, is not a physical element of the system. The combined signal of the adder 20 is supplied to the codec 14, where it is converted into an analog waveform and sent to the ISS 16 telephone. The ISS speaker can hear both the remote speaker and the analog telephone speaker. The combined digital signal of the adder 20 is also supplied to the EC1 30 to be used as a reference signal to cancel the stagnant listening echo from the ISS 16 telephone. A stagnant listening echo is created by the acoustic coupling of the voice received from the handset 50 to the microphone 52 in the ISS 16 telephone, and is modeled by passing it through the unknown echo channel 46 and added in the adder 54. It should be understood that the unknown echo channel 46 and the adder 54 are not elements included in the system itself, but are more parasitic results of the physical proximity of the microphone 52 and the speaker's earpiece 50. A similar signal flow is presented for the received voice supplied to the analog telephone 18. In the adder 24, the remote voice digitized in PCM form is added to the digitized ISS speaker voice samples, which have passed through.

P1536 / 99MX of the attenuator 66 and the delay element 64. The attenuator 66 is an optional feature that is used to prevent the voice of the ISS speaker from being performed along the return path of the SSS telephone (s). This could occur when the echo canceller 32 has not been fully adapted to the unknown echo channel 48 during the first few seconds of a call. The delay element 64 is a parasitic result of the attenuator 66 and, therefore, is not a physical element of the system. The combined digital signal of adder 24 is supplied to codein 42 where it is converted into an analog signal. The analog signal is then supplied to the hybrid 44 where it is converted into a 2-wire signal and then into the analog telephone 18 where it is received by the hybrid 58. The hybrid 58 converts the two-wire signal into a four-wire signal : two cables for the speaker 60 and two cables for the microphone 62. The combined digital signal from the adder 24 is also supplied to the EC2 32 where it is used as a reference signal to cancel the echo resulting from the hybrid 44. It creates a hybrid echo by an impedance uncoupling in the hybrid 44 which causes the received analog voice signal to be coupled to the transmitted voice of the analog telephone speaker, modeled to pass to P1536 / 99 X through the unknown echo canceller 48 and added to the adder 56. Again, it should be understood that the unknown echo channel 48 and the adder 56 are not elements included in the system itself, but are more parasitic results of the impedance uncoupling in the hybrid 44. The voice coming from the ISS speaker is received by the microphone 52 in the ISS 16 telephone and an echo signal is added to the voice, modeled by the adder 54, as analyzed in the above. The voice-plus-echo signal is supplied to the codec 14 in analog form and converted into digital PCM samples. The PCM samples are supplied to the adder 22 where an estimated echo signal is subtracted from it, resulting in an echoless signal that is then supplied to the adder 26. In the adder 26, the digitized voice of the analog telephone speaker is added to the echo voice canceled from the summer 22 and then supplied to the modem 8 for modulation and eventual transmission to the remote speaker. A similar process is presented for the voice transmitted from the analog telephone speaker. The voice coming from the analog telephone speaker is received by the microphone 62 inside the analog telephone 18. The analog voice is supplied to the hybrid 58 within the analog telephone 18, where it is converted into a two-wire signal. The two-wire signal is supplied to the hybrid 44 within P1536 / 99MX The ISS / SSS 2 unit is converted back into a four-wire signal: 2 cables for transmitted signals and 2 cables for received signals. An echo signal is added to the speech signal in the adder 56, as described above. The voice-plus-echo analog signal is then supplied to the codec 42 where it is converted into PCM digital samples and is supplied to the adder 28. An estimated echo signal generated by the adapter filter 36 is subtracted from the digital voice-plus-signal echo, leaving a canceled echo voice signal that is supplied to the adder 26. The speaker voice ISS is added to the voice without echo in the adder 26 and is then supplied to the modem 8 for modulation and transmission to the remote speaker. Figure 3 is a simplified functional block diagram of the echo canceller 30. The figure is equally applicable to the echo canceller 32. The complete details of the echo canceller are set forth in the aforementioned '405 patent. It should be understood that in the exemplary embodiment, echo cancellers 30 and 32 are, in essence, state machines with defined functions for each of the different operating states. The states in which echo cancellers operate 30 and 32 are: silence, remote voice, close voice, double conference and parasitic resonance. The following analysis is a description of P1536 / 99MX echo canceller 30 and the associated signal flows, however, the functionality is equally applied to echo canceller 32. In Figure 3, the received remote voice plus canceled echo voice from adder 28 is labeled x (n), while the voice signal received from the nearby ISS is labeled as v (n). It should be understood that both x (n) and v (n) are digital representations of analog voice waveforms. The remote input voice x (n) is stored in the buffer 100 for input to the status filter 102, the echo canceller filter 104 and the control unit 106. In the exemplary mode, the status filter 102 and the echo canceller filter 104 each have 256 sockets. It should be understood that the status filter 102 and the echo canceller filter 104 may use a greater or lesser number of taps depending on whether the echo to be canceled is a stagnant listening echo or a hybrid echo. Two filters adapted independently, the filters 102 and 104, track the unknown echo channel. While the filter 104 performs the actual echo cancellation, the filter 102 is used by the control unit 106 to determine which of the various echo canceller states 30 should be operated. For this reason, reference is made to filters 102 and 104, respectively, P1536 / 99MX as the status filter and the echo canceller filter. The advantage of this two-filter approach is that the filter coefficients of the echo canceller filter 104, which models the unknown echo channel, can be preserved more effectively without the risk of near speech degradation. The status determination of the status filter 102 is supplied to the control unit 106 where it is used to decide where to adjust the tap coefficients for the status filter 102 and for the echo canceller filter 104. The echo canceller filter 104 provides an echo replication signal and (n) to an adder input 22 where it is subtracted from the signal v (n 9. The echo replication signal and (n) is generated by estimating the impulse response of the echo channel. unknown during periods of near silence The output e (n) of echo suppressed signal resulting from adder 22 is fed back as an input to control unit 106 and is supplied to adder 26 and delay element 36, shown in the Figure 2. The advantage of having two echo cancellers in the design is that when a second speaker hangs up or picks up an additional line, the impulse response to the second echo canceller does not change.Therefore, the echo canceller filter 104 and the filter state 102 do not have to adapt their filter intake coefficients in response to the channel change. This P1536 / 99MX results in a more accurate echo estimation signal. In other words, the echo canceller 30 can be adapted when the ISS speaker is silent and the remote speaker or analog telephone speaker is speaking. Similarly, the echo canceller 32 can be adapted when the analog telephone speaker is silent and the remote speaker or the ISS speaker is speaking. Assuming that the active voice durations are distributed evenly among each speaker, each echo canceller can adapt two thirds of the time. If a single echo canceller was used, it could adapt only one third of the time. Another advantage of the present invention is that each echo canceller will converge faster than if a single echo canceller were used. The echo canceler filter 104 and the status filter 102 can only determine the characteristics of the unknown echo channel and converge when the near speaker is silent. If only one nearby speaker is assigned for each echo canceller, a near silent state is much more likely than if there is more than one nearby speaker assigned to a single echo canceller. The above description of the preferred embodiments is provided to allow any person skilled in the art to make or use the present invention. The various P1536 / 99MX Modifications to these modalities will be readily apparent to those skilled in the art and, the generic principles defined herein may be applied to other modalities without the use of the inventive faculty. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but to be in accordance with the broadest scope consistent with the principles and novel features set forth herein.

P1536 / 99MX

Claims (16)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and, therefore, property is claimed as contained in the following CLAIMS t 1. A cordless telephone to allow two or more users to communicate simultaneously between yes and with a remote user, comprising: a dedicated telephone to provide a first telephone entry; and at least one interface to receive an analog telephone input. The wireless telephone according to claim 1, wherein at least one interface comprises an RJ-11 telephone. The wireless telephone according to claim 1, further comprising at least one echo canceller. The wireless telephone according to claim 1, further comprising: a first codee connected to a three-way switch and to the telephone, to transform a first analog signal of the telephone into a first digital signal and to transform a second digital signal from the three-way switch in a second analog signal; a connected subscriber line interface P1536 / 99MX to at least one analog telephone and the three-way switch, to transform a third analog signal from the at least one analog telephone, into a third digital signal and to transform a fourth digital signal from the three-way switch, into one. fourth analog signal; the three-way switch connected to the codec, to the subscriber line interface and to a modem, to combine the first digital signal, the third digital signal and the digitized voice samples of the remote user. The wireless telephone according to claim 4, wherein the subscriber line interface comprises: a second codee; and a hybrid to provide an interface between the second codec and the at least one analog telephone. The wireless telephone according to claim 4, wherein the first digital signal, the third digital signal and the digitized speech samples are in the form of PCM data packets. The wireless telephone according to claim 4, wherein the three-way switch comprises: a first echo canceller connected to the P1536 / 99MX first codec, a first adder, a second adder and a third adder, to receive the first digital signal from the first codec and a first canceled canceled echo signal from the first adder and to produce a first echo signal canceled towards the second adder and towards the third adder; a second echo canceller connected to the subscriber line interface, the first adder, the second adder and the third adder, to receive the third digital signal from the subscriber line interface and a second canceled echo combined signal from the second adder and to produce a second echo signal canceled for the first adder and for the third adder; the first adder has a first input connected to the second echo canceller and the third adder, a second input connected to the modem to receive the digitized voice samples from a remote user, and an output connected to the first echo canceller and the first codee, the first adder serves to combine the canceled second echo signal and the digitized speech samples and produce a first combined canceled echo signal. the second adder has a first input connected to the first echo canceller, a second input connected to the modem to receive the samples P1536 / 99MX of digitized voice of the remote user and an output connected to the second echo canceller and the subscriber line interface, the second adder serves to combine the first canceled echo signal and a fifth digital signal in order to produce a second combined canceled echo signal; and the third adder has a first input connected to the second adder and the first echo canceller, a second input connected to the first adder and the second echo canceller and an output connected to the modem, the third adder to combine the first canceled echo signal and the second canceled echo signal in order to produce a third canceled canceled echo signal. The wireless telephone according to claim 7, further comprising: a first attenuator interposed between the second adder and the first echo canceller; and a second attenuator interposed between the first adder and the second echo canceller. The wireless telephone according to claim 7, further comprising: a first delay element interposed between the second adder and the first echo canceller; and a second delay element interposed between the first adder and the second echo canceller. P1536 / 99MX 10. A method for providing communication between at least three users, a first close user using a dedicated telephone, at least one other nearby user using an analog telephone and a remote user, comprising the steps of: digitizing a first analog signal from a first close user to produce a first digital signal; digitizing a second analog signal from at least one other nearby user to produce a second digital signal; adding a signal from a remote user with the first digital signal and providing a first combined signal to the at least one other nearby user; adding a signal from a remote user with the second digital signal and providing a second combined signal to the first nearby user; and adding the first digital signal with the second digital signal to provide a third combined signal to the remote user. The method according to claim 10, further comprising the steps of: reducing a first echo signal applied to the first analog signal using a first echo canceller; Y P1536 / 99MX reduce a second echo signal applied to the second analog signal using a second echo canceller. 12. A method for reducing echo signals in a wireless telephone, having at least one unknown echo channel, comprising the steps of: reducing a first echo signal applied to a first digitized speech signal; reducing a second echo signal applied to a second digitized speech signal; and combining the first reduced echo digitized speech signal and the second digitized reduced echo speech signal to produce a combined, digitized, reduced echo speech signal. 13. An apparatus for canceling both stagnation echo and hybrid echo, in a digital telephone system, the system comprises a remote speaker in wireless communication with at least two nearby speakers, nearby speakers use a wireless subscriber unit, the subscriber unit has at least two user interfaces, one interface is a dedicated telephone, and at least one other interface is a standard 2-wire telephone, the standard analog telephone connected to the subscriber unit via a hybrid of 4 to 2 cables, in where the subscriber unit allows simultaneous communication between the remote speaker and the first P1536 / 99MX nearby speaker who uses the dedicated telephone and a second speaker who uses the standard analog telephone; the apparatus comprises: a first means of echo cancellation located within the subscriber unit to eliminate the stagnant listening echo generated in the dedicated telephone; and a second means of echo cancellation located within the subscriber unit to eliminate the hybrid echo generated in the hybrid of 4 to 2 cables. 14. A method for canceling both the stagnant listening echo and the hybrid echo in a digital telephone system, the system comprises a remote speaker in wireless communication with at least two nearby speakers, nearby speakers using a wireless subscriber unit, the subscribing unit it has at least two user interfaces, one interface is a dedicated telephone, and at least one other interface is a standard 2-wire analog telephone, the standard analog telephone connected to the subscriber unit via a hybrid of 4 to 2 cables, where the subscriber unit allows simultaneous communication between the remote speaker, a close first speaker using a dedicated telephone and a second speaker using the standard analog telephone, the method comprising the steps of: P1536 / 99MX providing a remote digital voice signal and a first digital voice-plus-echo signal from the dedicated telephone to a first echo canceller; generating a digital echo-echo signal that approaches the staggered listening echo signal; subtract the digital echo-echo signal from the first digital voice-plus-echo signal, to produce a first echoed voice signal suppressed; providing the remote digital voice signal and a second digital voice-plus-echo signal from the standard analog telephone to a second echo canceller; generate an echo digital replica signal that approximates the hybrid echo signal; and subtracting the echo digital replica signal from the second voice-plus-echo signal to produce a second echo voice signal suppressed. The method according to claim 14, further comprising the steps of: combining the first suppressed echo voice signal and the second suppressed echo voice signal; and providing the combined echo voice signal suppressed to the remote speaker. The apparatus according to claim 13, wherein the first echo canceller means operates independently of the second echo canceller. P1536 / 99MX