Analog Call Forwarding and Digit Manipulation

The following figure shows the flow of dialed digits between two analog telephone installations within the Passport network.

In Example 1, the user connected to a station of the Los Angeles PBX attempts to reach PBX station 53456 in New York. To do that, the caller first dials trunk access code 7. Following receipt of a dial tone from the first available voice channel in the hunt group, he dials 21253456. One of the ingress numbers (phone number) configured in the Los Angeles ingress table is 2125****. Based on this number, the digits 21253456 are forwarded to the New York node.

At the New York node, some of the voice channels, whose phone numbers match digits 2125****, are indexed for manipulation string D3*****. As a result, the first voice channel matching 2125**** will drop 212, and forward digits 53456, ringing that PBX station. The call is established when the party at station 53456 answers.

In Example 2, the caller in Los Angeles is attempting to reach a party in the New York area whose telephone number is 7511234. To do that, the caller dials 7, then 21207511234. One of the ingress numbers (phone number) provisioned in the Los Angeles ingress table is 2120*******. Based on this number, the digits 21207511234 are forwarded to the New York node. At the New York node, some of the digital voice channels, whose first four digits are 2120, are indexed for manipulation string D4I9+*******.

As a result, the first voice channel matching 2120 will drop 2120, forward digit 9, wait one second (long enough to obtain a dial tone from its PBX), then forward digits 7511234. The call is established when the party at 7511234 answers.

Note: If the number of digits dialed by the user exceeds 7, as is the case in the two examples above, make sure that the maxNumFwdDigits profile parameter was previously set to a value of 8 or higher (default value is 7). Otherwise, the voice channel will stop collecting digits beyond 7, and no match will ever be established. To change the maxNumFwdDigits to a higher value, refer to the Voice Profile Options section.

The following figure shows a combination of digital and analog telephone installations within the Passport network. Here a Passport 4430/50/55 unit at Node 2 is configured with an E1 Voice Module (EVM) that includes six Digital Voice Modules (DVM), B1 through B6 in location B, and a dual-channel Analog Universal Voice Module in location C.

The six DVMs are configured with extension numbers 121# through 126#, respectively, and are logically connected over an E1 line to a digital PBX. Connection to the E1 line was previously established with the command CLI>set t1e1 ds0Connect.

Of the two analog voice channels in the AUVM, C1 is equipped with an FXS interface module configured with network extension number 131, and connected to an analog telephone. Analog channel C2 is equipped with an FXO interface module configured with network extension number 132, and connected to station 5678 of an analog PBX.

At the Node 1 end, the first three entries in the ingress table contain the ingress numbers associated with the Node 2 egress table.

Example 3

Assume that the user at Node 1 wants to contact station 2345 of the digital PBX at Node 2. To do that, the user dials 1252345. The digits 12# are used by the Voice Network Call Server (VNCS) to identify the destination of the call as Node 2. Based on ingress number 12*#, all seven digits are forwarded to Node 2. Here, 125 directs the call to DVM B5. As noted before, DVM channel B5 was previously connected to one of the E1 channels, possibly DS0 5 or any one of the remaining 29 channels.

Consulting the Node 2 egress table, the manipulation string of egress index 5 is D3#.

Note: The # sign is needed to insure that the remaining digits, whatever their number, are to be forwarded to the PBX. If a 4-digit numbering plan is used, the manipulation string could be changed to D3****.

As a result, the digits 125 are dropped from the string, and the remainder, digits 2345, are forwarded to the digital PBX, ringing station 2345. Besides station 2345, the user may access any other station on the digital PBX, or go off net via the PSTN connection, by dialing the appropriate combination of trailing digits, instead of 2345.

Summary for example 3

Example 4

To talk to the analog telephone connected to FXS voice channel C1, the user at Node 1 would dial 131. The digits 13* are also resolved to Node 2. Subsequently, digits 131 are forwarded to analog FXS channel C1, ringing the attached telephone. Note that there is no manipulation string associated with index 7 in the Node 2 egress table, since this telephone is the final destination.

Summary for example 4

Example 5

To reach a station, such as 5685, on the analog PBX of Node 2, the user at Node 1 would dial 1325685. Following address resolution, the digits 1325685 are forwarded to analog voice channel C2. This channel is physically connected to analog PBX station 5685. Based on the manipulation string associated with index 8, the digits 132 are dropped, and digits 5685 are forwarded to the PBX, ringing station 5685. As in the digital case, the user may access any other station on the analog PBX, or go off net via the PSTN connection, by dialing the appropriate combination of trailing digits instead of 5685.

Summary for example 5

End of Topic