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Basic ISDN
- 1. BASIC ISDN
- 2. Bean Cans !
- 3. Analogue Speech - SILENCE N S
- 4. Analogue Speech - Positive Pressure
- 5. Analogue Speech - Negative Pressure
- 6. The Traditional ‘Oscilloscope View’ MAX +VE Volts MAX -VE Volts 0 Volts
- 7. The Traditional ‘Oscilloscope View’ MAX +VE Volts MAX -VE Volts 0 Volts
- 8. The Traditional ‘Oscilloscope View’ MAX +VE Volts MAX -VE Volts 0 Volts
- 9. The Traditional ‘Oscilloscope View’ MAX +VE Volts MAX -VE Volts 0 Volts
- 11. The Analogue Telephone This signal is analogue ‘cos it is analogous to my vocal chords vibrating
- 14. Analogue Waveform Volts Time
- 15. Take Samples Volts Time
- 17. Pulse Amplitude Modulation t1 t2 t3 t4 t5 t6 Time Volts 125 s
- 18. Pulse Amplitude Modulation Timed Samples (every 125 s)
- 19. Pulse Amplitude Modulation 01111111 01111100 01101011 01010101 01011010 01001001 11011010 11010101 11101010 11101101 11110011 11111111 00000000 11001001 Amplitude Samples Timed Samples (every 125 s)
- 20. Pulse Code Modulation 01111111 01111100 01101011 01010101 01011010 01001001 11011010 11010101 11101010 11101101 11110011 11111111 00000000 11001001 X X X X X X X X X X X X X X X X X X X X X X X X Amplitude Samples Timed Samples (every 125 s)
- 21. Pulse Code Modulation 01111111 01111100 01101011 01010101 01011010 01001001 11011010 11010101 11101010 11101101 11110011 11111111 00000000 11001001 X X X X X X X X X X X X X X X X X X X X X X X X Amplitude Samples Timed Samples (every 125 s)
- 22. 01111111 01111100 01101011 01010101 01011010 01001001 X X X X X X
- 24. 01111111 01111100 01101011 01010101 01011010 01001001 X X X X X X 01011010 01010101 01111100 01111100 s1 s2 s3 s4 ? ? ? 125 s
- 25. 01111111 01111100 01101011 01010101 01011010 01001001 X X X X X X 01011010 01010101 01111100 01111100 s1 s2 s3 s4 01111111 01111100 01101011 01010101 01011010 01001001 X X X X X X 01011010 01010101 01111100 01111100 s1 s2 s3 s4 125 s
- 26. s2 01011010 s1 01101011 s1 125 s
- 27. 125 s 01000110 10101100 s2 s1
- 28. 125 s 01000110 10101100 32 samples s2 s1
- 29. 125 s 32 samples 8000 times per second 8bits x 32 x 8000 = 2,048,000 bits per second 1 frame s1 s2
- 30. 125 s 32 samples s1 s2 8000 times per second 0 16
- 31. 125 s 32 samples s2 0 16 Signalling DASS DPNSS Q931 Synchronisation
- 32. 30 samples
- 33. 30 samples OF WHAT ?
- 34. Audio Speech Tones Music
- 35. Video Security News Video-conference
- 36. Fax Group 2/3 sent as audio Group 4 after handshake 1.5 seconds/page
- 37. Data Files Programmes Control
- 38. Two Types Of ISDN Channel
- 39. Function Groups & Reference Points LT NT 1 NT 2 TE 1 TE 2 TA
- 40. Function Groups & Reference Points LT NT 1 NT 2 TE 1 TE 2 TA U T S R
- 41. ITU Reference Model for ISDN PTT Equipment at Phone Company Switch U Interface Termination Point T Interface Termination Point S Interface Termination Point Standard PSTN Equipment has an R Interface Termination Point U T S R TE2 TA TE1 TE1 NT1 NT2 ISDN Equipment that can connect directly to an ISDN Line Terminal Adapter used to connect TE2 devices to an ISDN line Equipment that cannot connect to an ISDN line Network Termination used to convert U into T interface Network Termination used to convert T into S interface
- 44. Basic Rate Interface The BRI is defined as two 64Kb/s Bearer (B) channels and one 16Kb/s Data (D) channel
- 47. NTE 8 The NTE8 (opposite) is the normal NTE within the customers premises for an ISDN2e connection. The NTE8 has TWO RJ45 sockets - ONLY ONE IS TO BE USED - the other is for testing purposes
- 52. Basic Rate For The Home Or Office
- 55. Multiple Devices And Multiple Numbers
- 56. S0 Bus RJ 45 Outlet Terminating RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet RJ 45 Outlet
- 62. PRIMARY RATE
- 64. NTE Status Lights BT Testing ON or Flashing Test Amber OK OFF Test Amber Network Faulty ON BT Red Network OK OFF BT Red Two or more inputs disconnected Flashing Customer Amber One input disconnected ON Customer Amber Inputs OK OFF Customer Amber NTE on Standby Battery Flashing Power Green No power to NTE OFF Power Green NTE on mains power ON Power Green Indication Status Light
- 65. Primary Rate Interface The PRI is supplied through a standard 2.048Mb/s E1 channel. This comprises of 30 64Kb/s B channels and one 64Kb/s D channel
- 67. DASS II Is presented Like This
- 68. ISDN 30
- 69. E1 Is Presented Like this
- 70. The Connection + Power Source/ Sink 2 8 - Power Source/ Sink 2 7 - Transmit/ Receive 6 - Receive Transmit 5 + Receive/ Transmit 4 + Transmit/ Receive 3 - Power Source/ Sink 3 2 + Power Source/ Sink 3 1 Polarity Signal Pin
- 82. Useful Numbers
- 83. Engineers Co-Op 0800 282 212
- 84. ISDN PRI Desk 0800 679 079
- 85. ISDN Helpdesk 0800 181 514
- 86. THE END
- 87. PDH
- 92. FAS
- 95. CRC-4 procedure At the receiving end the CRC of each submultiframe is calculated locally and compared to the CRC value received in the next submultiframe. If these do not coincide, one or most bit errors are determined to have been found in in the block, and an alarm is sent back to the transmitter, indicating that the block received at the far end contains errors.
- 104. NFAS - Alarm bit
- 112. THE END
Editor's Notes
- T1 = Time Slot 1 T2 = Time Slot 2 etc…. Every time slot is 0.000125 seconds apart (which is the sampling rate of 8KHz)
- We now have our samples of an entire conversation taken every 0.000125 seconds
- We now have a number of amplitude measurements taken at 0.000125 second intervals Each one of these samples is represented by an 8 bit binary number 8000 samples are taken every second Each sample is 8 bits long Therefore every second we need to transmit 8000 samples of 8 bits or 64,000 bits of information every second At this point the light should be starting to glow regarding the 64K channels available on Primary Rate ISDN
- However – now that we have our samples of our conversation we now also have a big empty hole between each sample!
- As nature abhors a vacuum – we need to fill this hole with something (MORE SAMPLES!!!)
- So, in our 0.000125 second space we are now starting to build up a nice collection of data samples
- BUT – we still have a hole I wonder how many samples we can cram into our 0.000125 second hole?
- WRONG!!! According to Nyquist there are; Lets look at a DS-1 signal which passes over a T-1 circuit. For DS-1 transmissions, each frame contains 8 bits per channel and there are 24 channels. Also, 1 "framing bit" is required for each of the 24 channel frames. 24 channels * 8 bits per channel + 1 framing bit = 193 bits per frame. 193 bits per frame + 8,000 "Nyquist" samples = 1,544,000 bits per second. And it just so happens that the T-1 circuit is 1.544 Mbps.--not a coincidence. Each of the 24 channels in a T-1 circuit carries 64Kbps. HOWEVER – as an American Nyquist was obviously WRONG! In the UK we have BT and a thing called an E1 This gives you a total available bandwidth of 2.048 Mb 2.048 Mb / 64K = 32 Available Channels SORRY!!!! In 1965 the standard appeared that permitted the TDM multiplexing of 24 digital telephone channels of 64 kbit/s into a 1.544 Mbit/s signal whose format was called T1 and which was also adopted by Japan. For the T1 signal, a synchronization bit is added to the 24 TDM time slots that correspond to the telephone channels, in such a way that the aggregate transmission rate is the result of the following calculation: (24channels x 8bit/channel + 1bit) / 125 ms = 1.544 Mbit/s where 125 ms is the PCM sampling period or interval between one sample and the next in the same channel . Europe developed its own TDM multiplexing standard a little later (1968), although its capacity was greater: 30 digital telephone channels of 64 kbit/s plus one for synchronization/transmission of alarms and another for signalling. The resulting signal was transmitted at 2.048 Mbit/s and its format was called E1. This European standard was adopted by the rest of the world except for the USA and Japan. For an E1 signal, the aggregate transmission rate can be obtained from the following calculation: (32channels x 8bit/channel) / 125 ms = 2.048 Mbit/s
- HOWEVER – now that we have our 32 samples we had probably better send some other information as well (synchronisation, maybe the callers telephone number etc). So, where’s a good place for this – at the beginning and in the middle! So, we will use channels 0 and 16 for control information and channels 1 to 15 and 17 to 31 for call information A BIT MESSY – Lets use channel 0 for synchronisation and channel 16 for everything else MUCH NEATER!
- Primary Rate NTE 4
- YES I KNOW we said 32 channels earlier BUT if you remember we gave channel 16 a specific purpose (DPNSS, QSIG etc) SO for many customers channel 16 does not exist (YEAH I KNOW channel 0 does not add up to much for them but for the sake of customer relations we will admit to one and keep the other up our sleeves for later!!