Shekaru da yawa da suka wuce, marubucin ya ziyarci wata kasuwa ta W6TRW ta shirya a tashar mota ta Northrop Grumman a Redondo Beach, California. Tsakanin talbijin masu siffar polar bear da tarin caja na waya da kayan wuta akwai akwatin katako mai kulle, rike da katako, da mai haɗin DB-25 a gefe. Kusa da mahaɗin akwai mai sauyawa: rabin duplex - cikakken duplex. Marubucin ya fahimci abin da yake. Modem. katako modem. Wato, modem ɗin haɗin gwiwa wanda Livermore Data Systems ya fitar a kusa da 1965.
Modem har yanzu yana kan kasuwar ƙuma. Nan da nan bayan daukar hoto, marubucin ya saya akan $20.
Tun da ba kowa ba ne ya san abin da modem ɗin acoustically guda biyu yake, ƙaramin digression cikin tarihi. Matsalar ita ce, a da, ba layukan kawai mallakar kamfanonin tarho ba ne. Haka kuma sai da suka yi hayar wayoyin tarho. Wadancan masu karatun da suka sami layin rana sun haɗa modem ɗin kai tsaye zuwa layukan tarho. Kuma a lokacin da aka yi wannan modem, an hana yin haka. Bisa ga dokar Amurka ta 1934, ba zai yiwu a haɗa wani abu zuwa wayar gida ta kowace hanya ba. A cikin 1956, bayan Hush-A-Phone Corp v. An sassauta dokar Amurka: na inji ya zama mai yiwuwa a haɗa. Hush-A-Phone ne .
An ba shi izinin haɗa na'urori daban-daban zuwa layin waya ta hanyar lantarki a cikin Amurka a cikin 1968 (). Amma har zuwa 1978, ba za a iya amfani da wannan damar ba, tun da ba a samar da jadawalin kuɗin fito, ƙayyadaddun bayanai da hanyoyin tabbatarwa ba. Saboda haka, daga 1956 zuwa 1978, yana da ma'ana don amfani da modem masu mu'amala da sauti da injin amsawa. A aikace, an sake su tsawon lokaci - ta inertia.
Wannan modem, yanzu yana tsaye akan teburin marubucin, shafi ne mai mahimmanci amma sabon abu a tarihi. Yana riga kafin maganin Carterphone don haka ba zai iya haɗa kai tsaye zuwa cibiyar sadarwar tarho ba. An tsara shi kafin haɓaka da yawa daga cikin kwakwalwan kwamfuta waɗanda ake la'akari da na zamani a yau. An fito da sigar farko ta wannan modem shekara guda bayan Bell 103, modem na farko da ya yi nasara a kasuwanci. Anan akwai babban misali na yawan yuwuwar da za a iya matsi daga cikin transistor goma sha uku kacal. Sannan an manta da wannan modem na dogon lokaci, har sai da aka harbe bidiyo guda biyu game da shi, daya a cikin 2009, ɗayan a cikin 2011:
Bidiyo mai rubutun ra'ayin yanar gizo phreakmonkey ya sami farkon kwafin modem tare da adadi mai lamba sama da 200. Irin waɗannan modem ɗin ana bambanta su ta hanyar nau'ikan goro, sassan waɗanda ke haɗa su ta hanyar dovetails. A cewar phreakmonkey, ana iya amfani da wannan fasalin don tantance shekarun da modem ɗin ke da shi, saboda dovetails suna da ƙwazo. An fara da lambar serial 850, an fara sanya modem a cikin akwati na itacen teak tare da haɗin akwatin. Daga nan aka fara haɗa sassan jiki da harsuna. Livermore Data Systems ana buƙatar yin modem cikin sauri da sauri.
A cikin 2007 blogger Brent Hilpert ya duba cikin irin wannan modem kuma . makircinsa yana da ban sha'awa musamman. Duk transistor guda goma sha uku da ke cikin modem sun kasance daidai kuma sun yadu a lokacin. An yi amfani da transistor PNP ɗaya na germanium a wurin saboda wani dalili da marubucin bai bayyana ba. Transistor na duk waɗannan nau'ikan har yanzu suna da sauƙin samun su a cikin tsoffin kayayyaki a yau. Kusan dala ashirin ne kawai - kuma a hannunku akwai cikakkun saitin transistor waɗanda dole ne a maimaita daidai modem iri ɗaya. Gaskiya, za a buƙaci wasu cikakkun bayanai, ciki har da ƙananan transfoma.
A zahiri, wani ya ciro na'urar dubawar sauti daga modem, sauran sun yi daidai da takaddun. Akwai alluna uku akan jirgin baya. A na farko - duk cikakkun bayanai na PSU, sai dai na'urar wuta, a na biyu - modulator, na uku - demodulator. An yi kwanan watan 2N5138 transistor: Makon 37, 1969. Ba zai yiwu a ƙara tabbatar da ranar sakin modem ɗin kanta ba, amma mai yiwuwa an kera shi kuma an tura shi kafin 1970.
Haɗin harshe da tsagi yana nufin modem na ƙarshen-saki
Marubucin ya sayi wannan modem don kawai ya ajiye shi a gida. Wannan modem na katako ne, amma da kyar wani mashawarcin marubucin ya yi tunanin yadda ya yi sanyi. Wannan wani abu ne na fasaha, wanda akwai abubuwa da yawa da ba a saba gani ba. Marubucin ya so ya gyara shi, amma ya gane cewa ba shi da amfani.
Da fari dai, don wannan kuna buƙatar nemo ainihin na'urar dubawar sauti. Saboda rashinsa, masu ziyartar kasuwar ƙwanƙwasa ba su fahimci irin na'urar da ke gabansu ba. Tambarin Livermore Data Systems da lambar serial sun kasance a wannan na'urar tun asali, kuma a yanzu rashinsu ya sa sauran maziyartan su iya gane kayan a matsayin modem, saboda su ba ma'aikatan gidajen tarihi na kwamfuta ba ne. Yana da jaraba, ba shakka, don buga cikakkun bayanai na na'urar mu'amala da sauti, amma shin hannaye za su kai ga wannan matakin?
Abu na biyu, ma'auni na yawancin capacitors tabbas "suna iyo" a ciki. Tabbas, yana da ban sha'awa don ɗauka da daidaita duk allon, amma idan marubucin yana son samun modem mai aiki tare da haɗakar sauti, akwai zaɓi mafi kyau.
Wannan ƙirar ƙira ce mai suna "“, wanda kungiyar Chaos Computer Club ta kirkira a shekarar 1985 saboda amsa irin wannan haramcin, wanda daga nan ya ci gaba da aiki a Jamus. Irin wannan modem ya fi sauƙi, kuma yana da ƙarin dama. Ana yin shi akan guntu AM7910, har yanzu ana samun lokaci-lokaci akan siyarwa, kuma yana aiki cikin sauri har zuwa 1200 baud. Yana yiwuwa a gina modem daga karce akansa da sauri fiye da kan transistor masu hankali.
Gabaɗaya, babu wata ma'ana a maido da wannan modem na katako, amma ya zama mai ban sha'awa sosai don tarwatsa shi, shirya hoton hoto kuma sanya komai tare kamar yadda yake. Kusan duk na'urorin lantarki suna kama da wannan daga ciki, har sai da microcircuits a ciki. Amma idan ba zato ba tsammani marubucin ya zo a kan na'urar dubawa ta murya mai dacewa da wannan modem, ya, ba shakka, zai sake tunani: watakila har yanzu yana da daraja a gyara?
source: www.habr.com