Nurfadillah Bercerita

Conference  Call atau umumnya dikenal sebagai call party sebenarnya merupakan teknologi yang sudah ditemukan sejak lama. Sebelum adanya layanan switching, pada mulanya semua sambungan telepon bisa saling berkomunikasi dari satu sambungan ke seluruh sambungan lainnya. Kalau dianalogikan ada 2 orang yang sedang terhubung dari ujung A ke ujung B, kemudian di tempat lain pelanggan C juga mengangkat gagang telepon. Tanpa perlu menekan apa-apa, pelanggan C ini langsung dapat terhubung dengan pelangaan A dan B yang sementara sedang melakukan pembicaraannya. Demikian pula apabila ada lagi pelanggan D, E, F dan seterusnya, yang ikut mengangkat teleponnya. Mereka pun akan langsung bergabung dengan sambungan yang telah terhubung.


Hal ini tentu saja menimbulkan banyak masalah atau kendala dalam penyaluran komunikasi. Salah satunya adalah kerahasiaan informasi menjadi tidak terjaga. Dan tidak efektif berbicara langsung dengan banyak pelanggan dalam satu waktu, karena mungkin pelanggan yang dituju bukan yang dihubungkan saat itu. Karena hal inilah, para penemu teknologi mulai merancang bagaimana caranya agar informasi yang dikirimkan bisa lebih efektif dan terjaga kerahasiaannya. Hingga ditemukanlah teknologi switching!


Dengan switching ini, pelanggan lebih terarah dan bebas menentukan pihak2 khusus yang ingin mereka hubungi, tanpa khawatir terganggu dengan pihak lain. Dimulai dari switching analog hingga berkembang ke switching digital. 

Setelah beberapa lamanya menikmati hubungan point to point antar pelanggan, layanan untuk conference ini dibuka kembali, tapi tentunya sudah dilengkapi dengan metode2 dan aturan2 khusus penyambungan agar tetap terjaga hubungannya. Misalnya dengan memilih sendiri pelanggan2 yang dituju dan bersedianya pelanggan yang dituhu untuk menerima atau menolak panggilan tersebut.


Sebenarnya yang terlibat dalam penyambungan ini bukan perangkat pelanggan atau User Equipment nya, tapi perangkat Switchingnya sendiri atau secara teknis diatur oleh PCM Multiplexing. Berikut metode yang digunakan dalam penyambungannya (maaf, karena belum sempat diterjemahkan, silahkan anda pahami sendiri) :



1. A method for completing conference call connections in a PCM division multiplex switching system having successive pulse frames each separated into plural time slots,comprising the steps of:

(a) forming an intermediate sum code word by adding code words received from subscribers to a conference call during their respective time slots,

(b) storing said intermediate sum code word by writing it into a first section of a conference call memory,

(c) reading out the intermediate sum code word from the conference call memory for each time slot of a conference call subscriber,

(d) storing the total sum code word in a second section of said conference call memory, said total sum code word representing the sum of all of the subscriber code words received during the previous pulse frame,

(e) reading out said total sum code word during the time slots assigned to subscribers of the conference call,

(f) interchanging the functions of said first and second memory sections during alternate pulse frames,

(g) introducing a delay between the reading out of an intermediate sum code word and formation of a new intermediate sum code word,

(h) introducing a delay between forming a new intermediate sum code word and storing it in the conference call memory,

(i) separating the reading and writing functions of said first and second sections of said conference call memory, and

(j) when conference call subscribers have consecutive time slots, omitting the delay interposed between formation of an intermediate sum code word and reading or writing of said conference call memory, whereby said intermediate sum is accumulateddirectly from code words received during consecutive time slots.

2. The method according to claim 1, wherein said code words are manifested in bit-parallel manner.

3. The method according to claim 1, including the steps of writing an intermediate sum, which is accumulated directly from code words received during consecutive time slots, into said conference call memory, inhibiting such intermediate sum frombeing added to, and overwriting such intermediate sum in said conference call memory with a new intermediate sum when subscribers to the conference call corresponding to said intermediate sum have consecutive time slots.

4. The method according to claim 1, wherein said first and second memory sections are read at different times during said time slots.

5. The method according to claim 1, including the steps of storing in said conference call memory bits identifying alternate pulse frames at storage locations corresponding to coordinated storage locations of said first and second sections ofsaid conference call memory, said bits being stored during the writing of an intermediate sum code word and being read out together with said intermediate sum code word, comparing the bit read out with the intermediate sum code word with a bit of thecurrent pulse frame, and storing the code word being received in response to an inequality as a new intermediate sum, without adding the existing intermediate sum.

Sumber metode : http://www.patentstorm.us/patents/4280216/claims.html