Timed Line Break Generator
Line-powered device generates 'recall' in response to a pre-programmed DTMF sequence.
The TLB1 is primarily designed for remote workers use who use Voice-over-IP for a phone connection to a head-office telephone system.
Although a VoIP system can be made essentially transparent to voice traffic, the support of legacy signalling, particularly the 'recall' signal, is poor or non-existant in most VoIP hardware. This 'recall' signal is used to put a call on hold or transfer it to another extension on the head-office PBX. It is sometimes called a TLB or FLASH signal and is implemented by the telephone momentarily going 'on-hook'.
In order to regenerate the recall signal at the head office end of the link, the TLB1 monitors the line and waits for a pre-programmed DTMF key sequence, such as '**'. Upon hearing this signal on the line the TLB1 generates the recall signal for the PBX, thus placing the call on hold. The remote VoIP user then gets the dial-tone or hold-tone from the PBX, just as if he were in the office.
The TLB1 enables users to benefit from the use of potentially free inter-office calls via the internet without sacrificing the capabilities of their office telephone system. |
