company, in which case the incoming call handling software will be required to place the call in 34.6.2 Outgoing call handling the appropriate company's queue for the operator to answer and flag the operator with the company name at the time the call is presented. Outgoing call handling used to be relatively simple on a PABX; the In many business applications the need for automatic call distribu- software was required to check if the originator of the call was tion (ACD) working is essential. This facility originally required permitted to dial that specific type of number e.g. national, interna- specially designed high traffic non-blocking systems with spe- tional etc. and then place the call with a free trunk handling software cialised control to route calls to agents who handled calls depending module and permit out dialing to commence. If the PABX had up the particular distribution selected by the business management. central speed dialling stores then these could also be handled by the The ACD system could comprise a high traffic PABX front ended outgoing call handling software and frequently the user would be by a call sequencer and a management system that displayed the permitted to speed dial international or national numbers but not calls waiting in the queues on special screens. As PABX are now make any other calls of this category. nearly all digital and non-blocking the PABX incoming call hand- Recent years has seen dramatic changes in the way outgoing call ling software has evolved to provide the functions of the ACD and handling software has had to be structured. The software now needs call sequencing system as part of the incoming call handling task. to decide which carrier to use e.g. in the UK the user has the choice The software is required to accept the incoming call request, route of BT or Mercury or his own private network, with breakout at the the call to a voice announcement, keep track of the time the caller nearest point to the destination on the PSTN. The number dialled by is listening to