PSTN Access for your Contact Center


The telephone lines that connect your call center to the rest of the world  are often the first link in a long chain of factors that affect the perceived service level received by your customer. It doesn’t matter how much you spend on a CRM package if customers receive a busy signal when they try to call you.


All too often, public switched telephone network (PSTN) access is simply ordered, with little or no thought as to how it dovetails with business objectives. However, there are many techniques and options available to set up your PSTN access arrangements. The ultimate goal of PSTN access engineering is to provide adequate (in terms of capacity), reliable and cost effective transport for telephone calls between the public telephone network and your premise.


PSTN Access Sizing

“Adequate” means that the bandwidth (or in voice parlance, the number of simultaneous two-way voice communication channels) is big enough to ensure that callers get through to your call center. It is impossible to put in enough trunks (see Table 1 – Glossary) to ensure 100 percent of inbound calls get into your automatic call distributor (ACD) at will. Disasters, marketing and dozens of other factors can drive unanticipated traffic loads into your center. 

PSTN Access for your Contact Center


This article originally appeared in Business Communications Review, December 2003 issue pp.36-41.  Updated September 2006 to reflect IP Telephony issues.

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