A certain syntax has been established for the billing unit. The unit is represented by two numbers separated by a forward slash. The first number represents the length of the first unit in seconds, the second number represents the length of all further units. Hence, the unit "60/1" means the first minute (60 seconds) of a call is always charged in full, even if the call was less than a minute. After the first minute, all additional fees are billed by the second. A 60/60 unit charges the full price per minute for each minute and part thereof. The different service providers frequently use the billing units 60/60, 60/10 or 60/1.