AT&T 585-300-903 manual Switched RS-232 Using Modems, 2Switched EIA RS-232 Networks

3-2Switched EIA RS-232 Networks

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SWITCHED RS-232 USING MODEMS

When a dedicated RS-232 network requires more than three AUDIX systems, or any time two systems are separated by a distance greater than two data sets can support, a switched RS-232 network must be formed. Modems convert the RS-232 signal into an analog signal for transmission through the switch to a colocated AUDIX system, or out of the switch across the public/private facilities to another switch.

Figure 3-1,Dedicated and Switched RS-232 Network for a Single Switch, shows four AUDIX systems serving the same switch. Notice that in this example there is a mixture of dedicated and switched connections. Incorporating two dedicated connections into this setup saves the customer the price of four modems. Whether this is a viable setup depends on the network usage between all systems.

If the network requires switched access to all RS-232 channels, the network would look like Figure 3-2,Switched RS-232 Network for a Single Switch.

Figure 3-3,Switched RS-232 Network for Separate Locations, shows three AUDIX systems serving switches at different locations. This setup also presents a mixture of dedicated and switched connections. The assumption is that the two systems serving the same switch will have much more use for a network connection, so a dedicated connection is provided. For the occasional connection to/from the other site, a switched connection is used.

If Call Detail Recording is required, a PC can be included in a switched RS-232 network using a spare dedicated RS-232 connection or through a switched RS-232 connection. Figure 3-4,Switched RS-232 Network for Separate Locations and a PC, shows a switched connection. The PC has dial-up access to any AUDIX system in the network.