Digital HierarchyT1STS4

OC1DS3

DS0

STM 16 OC 256T4

Parallel Transmission

Serial TransmissionTransmission Modes

Data TransmissionData TransmissionSynchronousSerialParallelAsynchronous

Parallel Transmission

Serial TransmissionThe 8 bits are sent one after another

Synchronous Transmission

Asynchronous Transmission

Voice Digitalization

T1 is made up of 24 DS0 LinesT1 speed is 1.544 MbpsT1 Hierarchy10122223DS0s00T1 Framing bits 100011011100

T1 HierarchyT1 frame is made up of 192 (Voice) + 1 (parity) bits

T1 frame is transmitted in a time of 0.125 milli seconds

giving a total speed of 193/0.125 = 1544 kbps or 1.544 Mbps

T1 HierarchyT1 is made up of 24 DS0 LinesT1 speed is 1.544 Mbps0122223T1T1T1CT1CT2T2T2T2T2T2T2T3T3T3T3T3T3T4DS0sT11.544MbpsT1C3.152MbpsT26.312MbpsT344.736MbpsT4274.76MbpsDS0 64kbpsT2T3T1 = 24 DS0sT1C = 48 DS0sT2 = 96 DS0sT3 = 672 DS0sT4 = 4032 DSOs

E1 InterfaceSupports 32 user channels( each of 64 kbps access rate)Provides 2.048 Mbps access rateMostly only 30 are dedicated channelsE1 supports 3 different bit structuresFrame Multi frame Unframed The mode of operation dictates how the bits are structured

E1 is made up of 32 DS0 LinesE1 speed is 2.048 MbpsE1 Hierarchy0123031DS0sE1 Frame 2100110110101010111110000E1 Frame16100110110101010111110000E1 Frame 11001101101010101111100000131

TS 0TS 1TS 31E1 Frame 256 bitsMultiframeE1 basic frame consists of 256 bits 32 time slotsEach time slot contain 8 bits And provides 64kbps throughput E1 TIME SLOTS FUNCTIONS:TS0 - Synchronization - alarms - messagesTS16 - for Signaling - can carry data as well(TS1-TS15) & (TS17-TS31)Structure of E1 Frame011011 (bits 2 7)1234567891011121314150

E1 Hierarchy TS0 TS1 TS30 TS31 E1 takes 32 DS0 Channels

30 Slots for Voice

Two Special Timeslots

TS0 is used for Framing and Synchronization

TS16 is used for signalingSpeed of an E1 line is 32 @ 64 kbps = 2.048 Mbps TS2 TS16

ITU-T Rec. G.704 E1 CAS Transmission FormatTime Slot 16 : Frames 2 through 15 are the same as frame 1Time Slot 0: Even number frames 2 through 14 are the same as frame 0Time Slot 0: Odd number frames 3 through 15 are the same as frame 1

1 = bit set to 1 0 = bit set to 0 1/0 = speech / signalling (varying data) X = unassigned bit (normally set to 1)

Fr. Ch.Ch.

1 116 2 217 3 3 18 : : :15 15 30

SpeechCh. 1-15SpeechCh. 16-30SpeechCh. 1-15SpeechCh. 16-30FrameTime SlotFrame Alignment WordMulti-Frame Alignment WordChanges to 1 on loss of distant multiframeChanges to 1 on loss of distant frame(remote alarm)Not-Frame alignment wordLSB

I1ANNNNN12345678I001101112345678Bit #->Bit #->Odd FramesEven FramesInternational BitInternational Bit1 Indicates ODD Frame0 Indicates EVEN FrameNational BitsYellow Alarm(Alarm = 1)(Normal = 0)Frame Alignment patternE1 Framing Format

12345678CI0011011Frame 04 Bit CRC0 Indicates EVEN FrameFrame Alignment pattern12345678C300110110 Indicates EVEN FrameFrame Alignment pattern12345678C200110110 Indicates EVEN FrameFrame Alignment pattern12345678C400110110 Indicates EVEN FrameFrame Alignment patternFrame 2Frame 4Frame 64 Bit CRC4 Bit CRC4 Bit CRCTimeslot 0 Optional Operation (With CRC-4)

OC 151.840 MbpsOC 3 155.520 Mbps

OC 9 466.560 Mbps

OC 12622.080 Mbps

OC 18 933.120 Mbps

OC 24 1244.160 Mbps

OC 36 1866.240 Mbps

OC 48 2488.320 Mbps

OC 964976.640 Mbps

OC 192 9953.280 MbpsSONETSTS 151.840 Mbps

STM 1 155.520 Mbps

STM 3 466.560 Mbps

STM 4622.080 Mbps

STM 6933.120 Mbps

STM 81244.160 Mbps

STM 121866.240 Mbps

STM 162488.32 Mbps

STM 324976.640 Mbps

STM 64 9953.240 MbpsSDHOptical Hierarchy

Thank You!

Made up of 16 consecutive framesThis frame structure is used for two purposes 1.signaling(CAS): here each channel has a predetermined frame. Half of the TS16 is dedicated for the channel signaling information signaling (CCS): here one or more channels of 64kbps are dedicated for signaling 2. Error correcting code mechanism: CRC is carried in TS0.

Multi Frame Structure

E1 Timeslot 16

E1 Timeslot 16