Situation:
The topology of voice communication network of the IPC application is shown in the illustration below.
In the IPC application, there are two Box phones on the local site and one IPC phone on the remote site. According to business needs, when the IPC phone speaks, the two Box phones can hear it speak at the same time. When the two Box phones speak, the IPC phone can hear them, but the two Box phones cannot hear each other.
Solution One:
The customer deploys a Loop-AM3430 and uses its combination of the 4-wire E&M card and FXS card to solve this problem. Loop-AM3430 is an economical, cost-effective Access DCS-MUXs that combines various digital access interfaces into T1/E1 or FOM lines for convenient transport and switching.
Downstream channel setup (red line): The time slot 1 of E1 is unidirectional cross-connected to port 1 and port 2 of the FXS card connected to BOX phone A and BOX phone B, and when the IPC phone speaks, both Box phones can hear it.
Upstream channel setup (blue line): Port 1 and port 2 of the FXS card are cross-connected with Port 2 and port 3 of the E&M card, respectively. Because the pins of each port of the E&M card, which send or receive voice signals, are separated to form an audio isolation between the Box Phone A and the Box Phone B, the two Box phones cannot hear each other. The TX pins of port 2 and port 3 ports of the E&M card are linked to the RX pin of port 1 of the E&M card by wires for the purpose of audio mixing. Then, the port 1 of E&M card is unidirectionally cross-connected to the time slot 1 of E1 so the IPC Phone can hear both BOX phone A and B speaking.
Solution Two:
The Loop-AM3440 series products are Access DCS-MUXs which support multiplexing of various digital access interfaces into E1 or T1 lines for convenient transport and switching.
In this application, the customer can also use the AM3440 and its combination of ABRA, FXS and E1 cards to meet the requirements of the user.
The setting method is as follows:
The time slot 1 of E1 is cross-connected to one of the Master ports of the ABRA card. The port 1 and port 2 of the FXS card connected to the two Box phones are separately cross-connected to two of the Slave ports of the ABRA card.