James Wilson, Call Center Pros, 4/6/2016
TNT (also known as Transfer Connect) is a transfer mechanism offered by some U.S. PSTN service providers (like AT&T & Verizon). With this transfer method, inband DTMF tones are outpulsed to the PSTN by CVP. These inband tones act as a signaling mechanism to the PSTN requesting a transfer to be completed. A typical DTMF sequence is *8 ####, where #### represents a new routing label that the PSTN understands. Upon detection of a TNT DTMF sequence, the PSTN drops the call leg to the ingress gateway port, and then re-routes the caller to a new PSTN location, such as a TDM ACD location. (This paragraph is borrowed from the Cisco website, I will rewrite below for anyone to understand in a call center environment)
Let’s imagine a phone call first goes to a Filipino call center and the agent wants to transfer the USA caller to a USA based agent to up-sell. We would work with our AT&T re-seller to set-up a preprogrammed TNT dedicated for the toll free line the caller first called. The Filipino agent would dial “*T” and the “T” is for “transfer”, actually the agent would dial “*8”. AT&T would know the the DTMF is heard it will drop the Filipino call center and will blindly transfer the call to the USA call center number “8005551212”. If the Filipino agent were to transfer from his phone directly the call path would be USA to Philippines to USA but the call path of the TNT call would be USA to Philippines and a second call USA to USA. The TNT call will sound much better and have a lower cost per minute. The only downside to the TNT call is that the call is a blind transfer, the Filipino agent should notify the caller that the caller will transferred without passing previous information gathered.
The way Cisco explains it, with the agent dialing *8 8005551212 could expose the call center to fraud. A hacker could call a company number with TNT completely open for both the agent or the caller to dial *8 and any number is very risky. A Takeback-N-Transfer is powerful tool but must be set up correctly and double-checked that no holes are open for hackers.