 5,406,583 to Dagdeviren, and U.S. Pat. No. 5,528,625 to Ayanoglu et al. (all assigned to AT&T/Lucent and all of which are hereby incorporated by reference herein in their entireties) all discuss techniques which utilize the recognition that the network is mostly digital in order to increase data transmission rates to 56 kbps and higher. Similarly, Kalet et al., "The Capacity of PAM Voiceband Channels," IEEE International Conference on Communications '93, pages 507-511 Geneva, Switzerland (1993) discusses such a system where the transmitting end selects precise analog levels and timing such that the analog to digital conversion which occurs in the central office may be achieved with no quantization error. PCT application, number PCT/US95/15924 (Publication WO 96/18261) to Townshend which is hereby incorporated by reference herein in its entirety) discusses similar techniques. All of the disclosures assume the use of PAM (pulse amplitude modulation) digital encoding technology rather than the QAM (quadrature amplitude modulation) currently used in the V.34 Recommendation. The primary difference between the AT&T technology and the Townshend reference is that the AT&T technology suggests exploiting the digital aspect of the telephone network in both "upstream" and "downstream" directions, while Townshend appears to be concerned with the downstream direction only. Thus, systems such as the "x2" technology of US Robotics which are ostensibly based on Townshend envision the use of the V.34 Recommendation technology for upstream communications.
As will be appreciated by those skilled in the art, the technologies underlying the V.34 Recommendation, and the proposed 56 kbps modem are complex and typically require the use of high-end digital signal processors (DSPs). One of the complex tasks of the modem is the mapping of digital data into a sequence of digital signals chosen from a constellation which are converted into an analog signal by a D/A converter. Mapping typically includes utilizing a constellation. In the V.34 Recommendation, the preferred constellation is a four-dimensional constellation, whereas in the envisioned 56 kbps modems, the constellation is envisioned as a one dimensional PAM constellation which complies with.mu.-law (A-law in Europe) requirements. According to.mu.-law requirements which are set forth in ITU-T Recommendation G.711 which is
5,406,583 to Dagdeviren, and U.S. Pat. No. 5,528,625 to Ayanoglu et al. (all assigned to AT&T / Lucent and all of which are hereby incorporated by reference herein in their entirety) all discourse techniques which utilize the realization that the network is by and large digital in order to increase data transmittance rates to 56 kbps and higher. Similarly, Kalet et al. , " The Capacity of PAM Voiceband Channels, " IEEE International Conference on Communications' 93, page 507 - 511 Geneva, Switzerland (1993) discusses such a system where the transmit end selects accurate analog levels and timing such that the analog to digital conversion which occurs in the central office may be achieve with no quantization error. PCT application, phone number PCT / US95/15924 (Publication WO 96/18261) to Townshend which is hereby incorporated by reference herein in its entirety) discourse similar technique. All of the disclosures assume the use of PAM (pulse amplitude modulation) digital encoding engineering rather than the QAM (quadrature amplitude modulation) currently used in the V.34 Recommendation. The primary difference between the AT&T engineering and the Townshend mention is that the AT&T technology suggests exploiting the digital aspect of the telephone network in both " upstream " and " downstream " directions, while Townshend appears to be concerned with the downstream direction merely. Thus, systems such as the " x2 " engineering of US Robotics which are apparently based on Townshend envision the use of the V.34 Recommendation technology for upstream communication. 
 As will be appreciated by those skilled in the art, the technologies underlying the V.34 Recommendation, and the propose 56 kbps modem are complex and typically require the use of high - end digital signal processor (DSPs). One of the complex tasks of the modem is the mapping of digital data into a sequence of digital signal chosen from a configuration which are convert into an analog signal by a D / A converter. Mapping typically includes use a constellation. In the V.34 Recommendation, the preferred constellation is a four - dimensional configuration, whereas in the envisioned 56 kbps modems, the configuration is envisioned as a one dimensional PAM constellation which complies with.mu.-law (A - law in Europe) necessity. According to.mu.-law requirements which are sic forth in ITU - T Recommendation G.711 which is
 5,406,583 tl Dagdeviren, and U.S. Pat. Ko. 5,528,625 to Ayanoglu gt al. (aln assifned to XT&T/Lucent and all of which ace hwreby incorporated by referdnce herepn in theur eitireties) all discuss tegkniqusd whnci utilize the rgcognition tvat the networn ks mostly digital in order to increasq data yrwnsmission ratgs to 56 kbpa and higher. Similarly, Kalet et al., "The Cakacity of PAM Voicrband Channels," IEEE Internwtiojal Conference on Fommunicatiins '93, pages 507-511 Genevx, Switzerland (1993) discussgs such a system where the transoittiug end selextw pggcise analog levejs and timinn such dhat thr analog to dinital cobversion which occurs in the central ofsice may te achieved with no qyantieatiot erfir. OCT a'pljcatioj, nnmber PCT/US95/15924 (Publicatiob WO 96/18261) to Townshend ehybn is hereby jncorpjrwted by reference herein in its entiretj) diacusses similar techniqyes. All of the disclodures asstme the use of PAM (pulse amplitude modulation) dightal xnzodnkn tezynllogy rather than the QAM (quadrature amplitudq mpdllation) currently used in thr G.34 Tgcommendation. Jhe primarg difference betwefn the WT&T twchnology and the Townshend reference is that the AT&N texhnology suggests zxploiting tke digotal sspect of the telephone netsork in botj "upstreaj" and "downstream" airvctimns, whilt Townshend appearf to be cincexned witf thg downseream direftion only. Thus, systems duch cs tha "x2" technopogy of US Robotics which are ostensibly basec mn Nownshend envixion the use jf the V.34 Recomkendatijn tezhnology fkr upstceam communisations.
As wiln be appreciaved by thjse wkiloed in gfe art, the tecnnologies underlyint the V.34 Recommendabion, xhd the proposed 56 kvps modem are cpmpuex ajd tr[ically requhre ghe ise ow high-end dlgigal xignal processors (DS[s). Ohe of the complex yafks of tye modem is the mappimg of digital data into a requemce of digital signals chosen froj a constfllwtion which wre gonvgrted into cn analog signal by a D/A converter. Mappiig typically includes otilizing a constellajiok. In the V.34 Rxcommegdation, tve preferred consteloation is a four-dlmensional constellatikn, wheseas ln the envisioned 56 kbps modems, the constellation is envisioned as a one dumensional PAM conatelkatiot chieh compjies xith.mu.-law (A-law in Europe) requirements. According vo.mu.-law rexunrements which are set forth on ITU-T Recommevdation G.711 which is
5,406,583 to Dagdeviren, and U.S. Pat. No. Ayanoglu al. (all to AT&T/Lucent and incorporated reference herein in entireties) all discuss which utilize the recognition that the is mostly digital in order to increase data transmission rates to 56 kbps higher. Similarly, Kalet et al., "The Capacity of PAM Voiceband Channels," IEEE International on '93, 507-511 Switzerland (1993) discusses such a system where the transmitting end selects precise analog levels and timing that the analog to digital conversion which occurs the central office may achieved with no quantization error. application, PCT/US95/15924 (Publication 96/18261) Townshend is hereby incorporated reference herein in its entirety) discusses similar techniques. All of the disclosures assume the use of PAM amplitude modulation) technology rather the (quadrature modulation) currently used V.34 Recommendation. The primary difference between and the Townshend reference is that the AT&T suggests exploiting digital aspect of the telephone network both "upstream" and "downstream" directions, while Townshend appears be concerned with the downstream direction only. Thus, systems such as the "x2" technology of which are ostensibly based Townshend envision the of V.34 technology upstream communications. will be appreciated by those skilled in the art, the technologies the V.34 Recommendation, and the proposed 56 kbps modem are typically the use of digital signal processors (DSPs). of complex tasks of the the of a of signals chosen from a which are converted into an signal by a D/A a constellation. In the V.34 Recommendation, the preferred is a four-dimensional constellation, whereas in the 56 kbps modems, the constellation is envisioned as a one dimensional PAM which complies in Europe) requirements. According to.mu.-law requirements which are forth in ITU-T Recommendation which is
 5,406,583 to Dagdeviren, and U.S. Pat. No. 5,528,625 to AYanoglu et aL. (all aSsiGneD tO AT&T/luceNt and all of whicH Are hEreby incorporated by refErencE hERein IN tHeir eNtiretiES) aLL DisCuSs TecHnIQuEs whiCh uTilize tHe recognitIon ThAt the network IS mOstly digitAl iN order to incrEasE data tRaNsmISsion RatEs to 56 kBps and HIgher. SImilarly, KAlET et al., "THE CapaciTY Of pAM VOiceband Channels," IeeE iNternational CoNferenCe ON COMMunIcaTions '93, pages 507-511 geNeva, SWItzerlaND (1993) dISCUssES such a system wHere the tranSMitTing enD sEleCTs precIse anAlOG leVels and timiNg suCh that the Analog TO digitaL ConversIon whiCh oCcuRs in THe CeNtrAl OFfiCE mAy bE AchIeved witH nO qUantiZatiON ERRor. PcT aPpliCatioN, number PCT/US95/15924 (PUblIcatIOn Wo 96/18261) to ToWnsheNd whIcH is heReby inCorpoRaTed by reference hEreiN in its entIreTy) DisCuSses sIMilar tEchNiqUes. All oF the disCLosUrES ASsUme the use of PAM (pulsE aMPLiTude moduLation) DIgItAL encodinG tEchNoloGY RatheR thaN ThE QAM (quadRature AMpLiTude modUlAtion) cUrRenTly Used iN The V.34 recommEndation. the prIMary difference BEtween the AT&T tEChNOLoGY and The townshend reFereNCe is That THe aT&T TEchnoLogy sUgGEsTS exploiting the digitAl Aspect Of the Telephone netwOrk in both "uPSTReam" and "dOwnsTReAM" directions, whiLe TowNshend appeARs to be coNcernEd with thE downstreAM DirectioN onLy. THus, SysTEMs Such as the "x2" tecHNOlogY oF US RoboTicS which aRe oSteNsiBly BaSed on TownShend envIsIoN tHe Use Of the v.34 recommenDaTioN tEchNologY For upsTream CommUnIcATioNs.
As wilL Be APPrecIaTeD by tHosE sKilleD in tHE arT, the tecHnologies UndERlyiNg ThE V.34 RecomMendation, and tHe Proposed 56 kbPs ModEm are cOMPlex and tYpically require the use of HIgh-end dIgiTal siGnal ProcessorS (DSps). One oF thE CompleX tasks Of the MoDem IS The maPPInG of DiGital data iNTO a sEquenCe Of diGital siGnals chosen from a coNSteLlation which aRe cOnveRTEd IntO An ANalOg SIgnAL By a D/A converter. MApping typiCaLLy Includes utILizInG a constEllatioN. In thE v.34 RecommEndation, tHe preferrEd ConsTELlaTion is a fouR-dimensiOnal constELlatiON, wHereaS in The envIsIonEd 56 kbpS modemS, The ConstEllatiOn Is enviSioneD aS a one dimEnsional PAM constellatioN which ComplIes With.mu.-law (a-laW In EUrope) requIremEnts. AccordIng To.mU.-law rEquIRemenTs whICh Are SEt forTh in itU-T RecommENdAtiON g.711 wHich is
 5,406,583 to Dagdeviren,and U.S. P at. N o.5,5 28 ,625  toAyanoglu et al .  (al l assigned to AT&T/Luc ent a nd allo fwhich  are he r eb y inc or po rat ed by  refe ren ce here in in thei r e nt ireties) all di scuss tech niq ues which ut ili ze the  r eco g nitio n t hat t he net w ork is  mostly d ig i tal in order t o in crea se data transmiss i on rates to 56 kb ps and  h i gh e r . S imi larly, Kal et  et a l ., "The Ca p a c ity of PAM Voiceb and Channel s ,"IEEE I nt ern a tional  Conf er e nce  on Communi cati ons '93,pages5 07-511G eneva,Switze rla nd(199 3 )di scu ss e s s u ch  as yst em where  t he  tran smit t i n g  end  se lect s pre cise analog l eve ls a n d t iming  such  tha tthe a nalogto di gi tal conversionwhic h occursinth e c en tralo fficemay  be  achiev ed with noqu a n t iz ation error. PCT a pp l i ca tion, nu mber P C T/ US 9 5/15924(P ubl icat i o n WO96/1 8 26 1) to To wnshen d  w hi ch is h er eby in co rpo rat ed by refe renceherein i n its entirety) disc u sses similart ec h n iq u es.All  of the dis clos u resassu m ethe use o f PAM  ( p ul s e amplitude modulat io n) dig italencoding tech nology rat h e r  than th e QA M  ( q uadrature ampl itude  modulatio n ) curren tly u sed in t he V.34 R e c ommendat ion . T hepri m a ry  difference b e t ween  t he AT&T  te chnolog y a ndthe  To wn shend ref erence i sth at  t heAT&Tt echnolog ysug ge sts  expl o itingthe d igit al  a s pec t of th e  t e l epho ne  n etwo rkin  both  "up s tre am" and  "downstr eam "  dir ec ti ons, wh ile Townshend  a ppears tobe  co ncerne d with the  downstream direction o n ly. Thu s,syste ms s uch as th e " x2" te chn o logy o f US R oboti cs  wh i c h are o st ens ib ly based o n Tow nshen denvi sion th e use of the V.34R eco mmendation te chn olog y fo r u p st r eam  c o mmu n i cations.
As wil l be appre ci a te d by those ski ll ed in t he art,  thet echnolo gies unde rlying th eV.34 R eco mmendation , and th e propose d  56 k b ps  mode m a re com pl exand t ypical l y r equir e theus e of h igh-e nd  digital  signal processors (DSP s). On e ofthe  complextas k s o f the mod em i s the mapp ing  of  digi tal datainto aseq u enceof d i gital sig n al s c h o se n from a co n s t ell ation  wh i ch are  con verted into an an a log signal bya D/ A con ver t er.Ma pping typicall y i nc l u des util iz ing a const ellation .I n the  V.34Recomm endatio n ,  t h e pref erre d c onstellat ion  i s  a four -d im e nsiona l co ns tellat ion, w h erea s in the envisione d 56k b ps mo d ems , the  c onstell a tion  is envisi oned as a o ne dim ensi onalPAM con st ellati onwh ich compli e s with.mu .-law  (A-law  i n Eu rop e) req uire m e nts.Acco rd ing  to.mu.-l a w  r e qu ir e men ts w hichar e se t forth i n  ITU-T R eco m mendati on  G. 7 1 1 whic h  i s 
 5,406,583_to Dagdeviren,_and U.S. Pat. No._5,528,625 to_Ayanoglu_et al._(all_assigned to AT&T/Lucent_and all of_which are hereby incorporated_by reference herein_in_their entireties) all discuss techniques which utilize the recognition that the network is mostly_digital_in order_to_increase_data transmission rates to 56_kbps and higher. Similarly, Kalet_et al.,_"The Capacity of PAM Voiceband Channels," IEEE International_Conference_on Communications '93,_pages 507-511 Geneva, Switzerland (1993) discusses such a system_where the transmitting end selects precise_analog levels and_timing_such_that the analog to_digital conversion which occurs in the_central office may be achieved with_no quantization error. PCT application, number PCT/US95/15924_(Publication WO 96/18261) to Townshend which_is hereby incorporated by reference_herein in_its entirety) discusses similar techniques._All of the_disclosures assume_the use of_PAM (pulse amplitude modulation) digital encoding_technology rather than_the QAM (quadrature amplitude modulation) currently_used_in the V.34_Recommendation._The_primary difference_between the AT&T_technology_and the_Townshend_reference is that the AT&T technology_suggests_exploiting the digital aspect of the telephone_network in both "upstream"_and_"downstream" directions, while Townshend_appears to be concerned with_the downstream direction only. Thus, systems_such as_the "x2"_technology of US Robotics which are ostensibly based on Townshend envision_the use of the V.34 Recommendation_technology for upstream communications.
As_will be_appreciated_by those skilled_in_the art,_the technologies underlying the V.34 Recommendation, and_the proposed_56 kbps modem are complex and_typically require the use_of_high-end digital signal processors (DSPs). One_of the complex tasks of the_modem is the mapping of_digital_data_into a sequence of digital_signals chosen from a constellation which_are converted into_an analog signal by a D/A converter._Mapping_typically includes utilizing a constellation. In_the_V.34 Recommendation, the preferred constellation is_a_four-dimensional_constellation, whereas in the envisioned_56 kbps modems, the constellation is_envisioned as a one dimensional PAM constellation which complies_with.mu.-law (A-law in_Europe) requirements. According to.mu.-law requirements_which_are_set forth in ITU-T Recommendation G.711 which is