1. Consider a simple telephone network consisting of two end offices and one intermediate switch with a 1 MHz full-duplex trunk between each end office and the intermediate switch. Assume a 4 kHz channel for each voice call. The average telephone is used to make four calls per 8 hour workday, with a mean call duration of six minutes. Ten percent of the calls are long distance. What is the maximum number of telephones that an end office can support.

Hint: For this problem, you should assume that every call is exactly 6 minutes long and that every phone is used exactly 4 hours per day. You should also assume that all lines areoccupied at 100% during the 8 business hours and not used at all during the remaining 16 hours.

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2. Suppose we wish to implement a TSI system for implementing virtual circuit connections between 20 users for a business client. Assume that the client requires a maximum TSI delay of0.1 ms. Calculate the minimum TDM frame rate that will support this system. Also, calculate the maximum TDM slot duration per user.

Hint: You may assume that all other communication system delays aside from the TSI latency are negligible.