1. Sistem Telepon Pertemuan 11 Matakuliah: H0122 / Dasar Telekomunikasi Tahun: 2008

2. Bina Nusantara 2 Mahasiswa dapat menunjukkan konsep telepon, bagaimana koneksinya serta masalah yang ada pada sistem telepon. Learning Outcomes

3. Bina Nusantara 3 Terminology Central Office Switching Outline Materi

4. Bina Nusantara 4 Terminology – Local loop – Central office – Exchange – Trunk – Nodes – Super trunks – Tandem switch – Hierarchy Telephone System

5. Bina Nusantara 5 Three major components: – Local loops: twisted pair, analog signaling – Trunks: fiber optics or microwave, mostly digital – Switching offices Local Loop End Office Trunk Toll OfficeSwitching Office Intertoll Trunk Components

6. Bina Nusantara 6 Hierarchy

7. Bina Nusantara 7 Telephone Terminal – Local loop and Basic Phone – Calling sequence in phone Talking signals – Analog voltage Outgoing : 1 – 2 V at approx. 3 mA Incoming : half of outgoing signals Local loop characteristics – Envelope delay – Voice grade: Dial-up or switched line Dedicated, conditioned or leased line Terminal/Local Loop

8. Bina Nusantara 8 Loop signal level – Outgoing : - 10 and 0 dBm (600  ) – Incoming : - 42 to – 4 dBm – Termination on the Central office : 600  (or 900  ) Dialing – Pulse – Tone Dual-tone multi-frequency (DTMF) Terminal/Local Loop

9. Bina Nusantara 9 DTMF tones for each number Terminal/Local Loop

10. Bina Nusantara 10 BORSHT is the function of Subscriber loop interface circuit (SLIC) or line card in interfacing to a local loop – Battery : - 48 V dc – Over voltage : protection from excessive voltage – Ring trip : send 90 V 20 Hz ac signal with on hook : 2 s ; off hook : 4 s – Supervision : monitor the phone loop – Hybrid: Two-wire to four-wire converter or four wire terminating set: plit the local loop into 2 wire pairs. Trans-hybrid loss: – 30 to 50 dB of rejection – Test To test signals on the line and to check quality of loop and phone performance Loop Supervision

11. Bina Nusantara 11 Process calling : – Recognize the dialed digits – Make physical connection Connection : – Allow an analog signal voltage – Switching systems in matrix (crossbar or cross point switch) – For greater reliability used reed relay Central Office

12. Bina Nusantara 12 Common Channel Signaling

13. Bina Nusantara 13 Echo parameters: – Signal travel time and travel distance – Echo time = (distance/prop.velocity) x 2 To Cancel – Insert the reverse path loss Echo suppression by insertion of reverse path loss – Signal subtractions Echo suppression using the signal subtraction method – Digital signal processing New version of subtraction method, need arithmetic calculation (algorithm) – Four-wire method Echo Cancellation

14. Bina Nusantara 14 Echo Cancellation

15. Bina Nusantara 15 Four Wire

16. Bina Nusantara 16 Telah dipelajari gambaran umum sistem telepon. Telah dipelajari komponen telepon. Summary