variety of skills like using a computer to find and track loads for drivers to speaking multiple languages depending on the region or number of trucks they manage. Great customer service and good communication are vital for succeeding in this fast-paced environment. Capacity and metrics There is a limit to how many field units can be managed. This varies with circumstances. For example, a parcel delivery service dispatcher may encounter higher traffic around Christmas. Work is not evenly distributed across time: in any dispatch system there are traditional peaks or busy hours in requests for service. Some workplace cultures will allow longer wait times than others. Systems may use a Radiotelephony procedure to reduce talking time, allowing interaction with a larger dispatch fleet. Air traffic control and towing are two examples. The use of abbreviations or standard phrases can reduce the length of a transaction. Capacity may be reduced by relaxed voice procedure such as a delivery dispatcher giving a lengthy description of a customer complaint over the radio. It is generally accepted that giving field units computers connected with the computer-aided dispatch, or another enterprise system used for dispatch, unloads voice two-way radio channels and increases capacity. Users research information on their terminal or laptop instead of calling in with a request that the dispatcher do it. One source suggests radio traffic drops by 30% when computers are available to mobile users. Radio Measurements of communications may reflect dispatch capacity. A partial definition of capacity comes from the number of communications channels required to support a dispatch fleet. Two metrics of channel capacity may be: 1) the number of field units or resources dispatched, and; 2)number of push-to-talk presses per day. A resource may refer to a fire engine, tow truck, taxi, or refuse truck, regardless of how many walkie-talkies, mobile radios, or persons were fielded along with each resource. One suggestion is that 100 to 150 mobiles is the maximum practical on one channel. Another suggests 60-70 units as a maximum. The difference in these two ranges probably reflects the wording. For example, 120 mobiles may mean radios: 60 units each containing a mobile radio and an officer with a walkie talkie. For dispatch systems like take-out food delivery, where life safety is not an issue, delays may be acceptable. Delays increase capacity. Another possible measure of capacity is system push-to-talk presses. A 187-day study of four Contra