Practical SCADA for Industry David Bailey - FER-a

viii Contents
4.9.4 Dual tone multifrequency — DTMF 128
4.10 Analog tie lines 128
4.10.1 Introduction 128
4.10.2 Four wire E&M tie lines 129
4.10.3 Two wire signaling tie line 130
4.10.4 Four wire direct tie lines 131
4.10.5 Two wire direct tie lines 131
4.11 Analog data services 131
4.11.1 Introduction 132
4.11.2 Point-to-point configuration 132
4.11.3 Point-to-multipoint 132
4.11.4 Digital multipoint 133
4.11.5 Switched network DATEL service 134
4.11.6 Dedicated line DATEL service 134
4.11.7 Additional information 135
4.12 Digital data services 135
4.12.1 General 135
4.12.2 Service details 135
4.13 Packet switched services 136
4.13.1 Introduction 136
4.13.2 X.25 service 138
4.13.3 X.28 services 138
4.13.4 X.32 services 139
4.13.5 Frame relay 139
4.14 ISDN 139
4.15 ATM 141
5 Local area network systems 142
5.1 Introduction 142
5.2 Network topologies 143
5.2.1 Bus topology 143
5.2.2 Bus topology advantages 144
5.2.3 Bus topology disadvantages 144
5.2.4 Star topology 144
5.2.5 Ring topology 145
5.3 Media access methods 146
5.3.1 Contention systems 146
5.3.2 Token passing 147
5.4 IEEE 802.3 Ethernet 147
5.4.1 Ethernet types 148
5.4.2 10Base5 systems 148
5.4.3 10Base2 systems 150
5.4.4 10BaseT 151
5.4.5 10BaseF 153