Dial-peers are commands that are used to configure a local 3810 ports’ phone number and to determine which interface is used to call another 3810. There are 4 different types of dial-peers. The first one covered here is pots.

Syntax:

dial-peer voice <tag> pots

The tag is just a pointer used to make each pots dial-peer unique. It has no connection to a local or remote phone number. The only reason the tag is used is so that "dial-peer voice 222 pots" is different than "dial-peer voice 333 pots". The tag makes the dial-peers unique so they can have different commands associated to them.

The POTS dial-peer will contain the phone number of a local port. Don’t be confused by the destination-pattern. It is the phone number of the local port. Example:

These commands assign the phone number 101 to the local port 1/1. Notice that the tag used was 1. The following commands do the exact same thing; which is assign the number 101 to port 1/1.

Syntax:

dial-peer voice <tag> vohdlc

The tag serves the same purpose here as with the pots dial-peer. This dial-peer is used to call a remote port on another 3810. The destination-pattern is the number that is being called. Even though it is the same command syntax it has a completely different meaning when it is used with a dial-peer that isn’t POTS. Example:

The 3810 looks at the phone number that is dialed and matches it to a destination-pattern. When a complete match is made the call is placed. In the example above only one combination of digits will match. A call will be placed out serial 0 if the numbers 1000 are dialed. Notice that the session target doesn’t include a PVC after the interface. HDLC is point to point and doesn’t use PVCs.

This destination pattern is more flexible. The period is a wildcard. It matches any number. When 100 and any number are dialed the call is placed. This allows the numbers 1000 - 1009 to be called with this one dial-peer.

With this configuration a user will place a call when a one and any other three digits are dialed. The call will go out serial 2 in this example.

The other two types of dial-peers are:

Both of these types of dial-peers use the destination-pattern the same way that the vohdlc dial-peer does. It is the phone number of the remote side. The only difference is that the session target also needs a PVC number.

Example:

When a nine and any other 3 digits are entered a call will be placed out of serial interface number 1 on DLCI 100.

The number one and any other three digits will cause a call to be placed out of serial interface 2 over PVC 50. Note that ATM can only run on serial interface number 2.

Understanding dialing between 2 PBXs.

The usual setup for calling between 2 PBXs over a dedicated leased line is to just dial the phone number of the other side. For example, User A would just dial 6222 to connect to User B.

User A Leased User B

(5222) Phone-----| PBX |=======================| PBX |------Phone (6222)

The PBX is programmed to route all numbers that begin with a 6 out the trunk (leased line) to the other PBX. This is a very common function of PBXs. Another example is that the PBX is configured to connect to the public telephone network when a user dials a 9.

#10 WAN #20 User B

Now consider when you add a couple of 3810s and start sending your voice and data over the same WAN link. Now you have the PBXs and the 3810s involved in placing a call from User A to User B. You must still dial a number to access the trunk that is attached to the 3810, but another number is needed to reach the other 3810. The PBX can be configured to forward the digits it receives from the user to the 3810. Another method would be to have the user dial an access code which connects them to the 3810. The 3810 would provide dialtone and the user would enter the digits to place to call the other side. This is similar to the setup where a user picks up the phone, get dialtone from the PBX and dials a 9 to get dialtone from the public phone network. The user then dials to call the final destination.

The main difference with this setup is that the signaling is done between the 3810 and the PBX, not the remote PBX. Another important difference is that the 3810 needs to call the other 3810. At least one digit will have to be used to call the remote 3810. The examples after the excess digit playout section show how to setup calls between PBXs.

Excess digit playout.

Consider the following config.

As previously discussed, this assigns the phone number 5 to port 1/1. So when a phone call comes into the 3810 with the number 5 port 1/1 will answer. If this was an analog FXS port with a phone attached to it the phone would ring. If port 1/1 was a DS0 on the Digital Voice Module connected to a PBX then the 3810 would signal the PBX that this port is now off hook. If port 1/1 was an FXO port then it would provide dialtone.

Now consider that the line to the PBX from the Digital Voice Module is configured for E&M signaling. A user could call voice port 1/1 with the number 5 and also enter additional numbers that would be played out to the PBX. Example:

Calling side’s configuration:

Called side’s configuration:

On the calling side a call will not be placed until the destination pattern is completely matched. When the 3810 receives a 5 and any 3 additional digits a call will be placed out serial 0 over DLCI 40. The called side will receive an incoming call for 5xxx. Only the first digit, the 5, is needed to connect to port 1/1. The 3 additional digits, regardless of what they are, will be "played" out to the PBX. This is referred to as excess digit playout. If the incoming call was for 5223, then the digits 223 would be sent out to the PBX and extension 223 would ring. If the PBX had 4 digit extensions simply adding an additional period to the destination-pattern on the calling side would be the only configuration change needed.

In the software version MA4 and above the "forward-digit" command was added. It allows the user to configure the number of digits that are sent out the DVM. The default is to only play out the excess digits.

Example:

Calling side’s configuration:

Called side’s configuration:

Once again, the calling side a call will not be placed until the destination pattern is completely matched. When the 3810 receives a 5 and any 3 additional digits a call will be placed out serial 0 over DLCI 40. The called side will receive an incoming call for 5xxx. The difference here is that all of the digits will be forwarded to the PBX. The 5 and the additional digits. So with this configuration 4 digit extensions that start with a 5 can be called from the remote 3810.

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