uch a case, it may be necessary to change equipment at that base station and also perhaps to change the equipment or the location of surrounding base stations. These risks can be minimized if the site-survey team maintains good relationships with supportive busi- ness, community, and political groups. 32.5.2 Using existing transport routes The other criterion for locating base stations is the availability of backhaul transport between the base station and the mobile switching center (MSC). If the local telephone network has a transport backbone, then it certainly is worth our while to look for sites that easily and cheaply connect to it. If the base station site is not already on the PSTN backbone, then how close it is to the backbone does matter. The cost of leased transport lines is often based on the dis- tance from the facility to the backbone. Since the MSC almost certainly will be housed on the backbone, the distance from the base station to the backbone is a major factor in the cost of transport. Local exchange offices (LEOs) are often the connection point to the PSTN backbone. Before siting a base station near an LEO, it is also important to determine whether or not the LEO has the available capacity to support the additional lines you want to lease. Backhaul can be a very expensive part of operating a wireless telephone system, so it is important to find opportunities to get transport without paying a lot for it. Getting a few DS-1 or E-1 links from a base station to the backbone can be terribly expensive, so we should favor sites that already have low-cost backbone transport available to the MSC. Another factor is that it can take a long time to get off-backbone transport installed. Hav- ing base stations located where transport is already available means not having to work within the schedule constraints of installing new transport, perhaps to remote locations. An excellent candidate transport network is a cable television system. It already has high-capacity routes covering a large community of reside