+============================================================================+ ! ! ! BUSY VERIFICATION CIRCUIT part ][ By: The Wizard of the World of Cryton! ! ! +============================================================================+ [1]: Busy Verification circuits allow an operator to bridge the path between two connected ports, to verify that either or both are busy, and to speak to parties using the monitored ports (3-way conference). These circuits are considered to be service port circuits. One complete busy verification circuit consists of two PWBA's: 814434-026 and 814434-046. This figure shows the difference between a normal call connection and a busy verification connection as well as showing the interconnection of circuits associated with a busy verification call. Normal Call Connection Versus Busy Verification Connection ---------------------------------------------------------- NORMAL CALL CONNECTION: +----------+ +----------+ +-----------+ +------+ | | | | | TIMESLOT | Phone<--->|PORT A|<------>|- - - - - |<--->|- - - - - |<--->|- - - + | +------+ |PORT GROUP| |PORT GROUP| | ! | -------+ |MUX/DEMUX | | CONTROL | | ! | Phone<--->|PORT A|<------>|- - - - - |<--->|- - - - - |<--->|- - - + | +------+ | | | | |INTERCHANGE| +----------+ +----------+ +-----------+ BUSY VERIFICATION CONNECTION: +----------+ +----------+ +-----------+ +------+ | | | | | TIMESLOT | Phone<--->|PORT A|<------>|- - - - - |<--->|- - - - - |<--->|- - - + | +------+ |PORT GROUP| |PORT GROUP| | ! | -------+ |MUX/DEMUX | | CONTROL | | ! | Phone<--->|PORT A|<------>|- - - - - |<--->|- - - - - |<--->|- + + | +------+ | | | | | ! ! | | | | | | ! ! | BUSY +--------+ | | | | | ! ! | VERIFI- | + - - -|<----->|- - - - - |<--->|- - - - - |<--->|- + ! | CATION | * - - -|<----->|- - - - - |<--->|- - - - - |<--->|- - - + | CURCUIT | + - - -|<----->|- - - - - |<--->|- - - - - |<--->|- + | +--------+ | | | | | ! | | | | | | ! | TO/FROM +------+ | | | | | ! | MONITOR<->|PORT C|<------>|- - - - - |<--->|- - - - - |<--->|- + | ING OP. +------+ | | | | |INTERCHANGE| +----------+ +----------+ +-----------+ [2]: The busy verification circuit consists of three operational amplifiers and three sets of XMT OUT and RCV IN leads. See diagram... Busy Verification Circuit, Block Diagram ---------------------------------------- Amplifier A |\ +-----+ +------------>| \_____XMT_OUT_\| | ! +------->| / /| | ! ! |/ |CODEC| ! ! RCV IN | | ! ! +---------------------| | ! ! ! Amplifier B +-----+ ! ! ! |\ +-----+ *------------->| \____XMT_OUT_\| | | ! *---->| / /| | ! ! ! |/ |CODEC| ! ! ! RCV IN | | ! *-------------------------| | ! ! ! Amplifier C +-----+ ! ! ! |\ +-----+ ! ! +---->| \____XMT_OUT_\| | ! +-------->| / /| | ! |/ |CODEC| ! RCV IN | | +------------------------------| | +-----+ The inputs to each amplifier are the RCV IN signals from the two sets of leads not associated with that amplifier. Each RCV IN signal is the output of one of three CODEC's on PWBA 814434-026. The output of each amplifier is an XMT OUT signal, which is the input to one of three CODEC's. With this arrangement, two of the sets of busy verification circuit leads are switched into the two conversation paths that provide two-way communication between the two ports to be monitored. Signals on both paths then are fed into the amplifier associated with the third set of leads. This third set of leads is switched to the port that serves the monitoring operator. Thus, the XMT OUT lead from the third set carries voice signals from both monitored ports for transfer to the operator. The RCV IN lead of the third set carries the operators message to the parties on both monitored ports. [3]: Each of the operational amplifiers has unity gain. A coupling capacitor and voltage divider on the RCV IN analog input provides the proper frequency response and signal level for the amplifier inputs. [4]: The busy verification circuit is an optional and nonredundant portion of line and/or line and service group cells, using three port positions per cell. A component failure on this circuit never affects service to more then three ports and, therefore, is considered to be a minor failure. A component failure can cause loss of busy verification monitoring and/or loss of voice transmission through up to three ports. Thats all for this time, stay tuned for Part 3!!! Phreak on dudes! \ -===THE=WIZARD=]>>>)} / (*)- The *ELITE* Phreaker's Club -(*)