ions as Table 50.3) phone conversations from one location to another, possibly via one or more intermediate locations or sites. The telephone users do not expect to hear crosstalk from other telephone conversations sharing 600 channel FM 16QAM digital the same microwave system. Other sources of noise or interference analogue due to the microwave system should also be imperceptible. To the user, the fact that microwave is being used is irrelevant, and normal Bandwidth 10MHz 10MHz landline telephone quality is the minimum expected. Voice Chan Cap Another example is where microwave is used to interconnect data Max Data Cap 11.52MBit/s 25Mbit/s devices (computer terminals, keyboards, CRT displays, etc.) with control and monitoring devices at remotely located sites along a T-1 Capacity 10DS-1s 16DS-1s pipeline. If the microwave interconnection somehow caused data System Gain 110.4dB 111.5dB errors in outbound transmission, the terminal operator's controlling commands could be misinterpreted at the remote site resulting in a wrong and possibly costly erroneous action taking place (such as analogue FM and digital microwave are compared. In this case, the opening or closing the wrong valve, etc.). Similarly, if the operator digital system is superior in terms of data or T-1 capacity (by up to received erroneous gauge or meter readings due to a characteristic two times), but the analogue FM system is superior by about the of the microwave system, he might be encouraged to take an same factor (up to two times) in terms of voice channel capacity. erroneous action. The bandwidths are similar or the same. For the user, the microwave interconnection should be a transpar- ent portion of his total system. This is the objective of the micro- 50.3.7 Summary wave equipment designer and the microwave system designer. In order to achieve system transparency: Advantages of digital microwave are: 1. The equipment specifications must be consistent with trans- No difference between voice and data threshold to consider. parency in the sys