Connecting to a hardware PBX system

IVM is often installed in an environment where there is telephone system or PBX. Broadly the types of usage are for voice mail (recording messages for unattended phones), call attendant (playing a menu and directing calls accordingly) or other interactive voice response systems.

For professional setups you need to know your PBX well. If you don't know your PBX and what it can do read the manual or call in the supplier. The information that follows is intended for more telephone-technical people.

One requirement that applies in all circumstances is that the calls for IVM be directed to analog ports. IVM will almost always be running on a computer that has a professional telephony card (see http://nch.com.au/ivm/modems.html for a list of recommended telephony boards and voice modems). These boards all have analog RJ12 style sockets. The first step is to ensure you have analog ports wired from your PBX.

The next step is to program your PBX to direct the calls as required to those ports.

Voice Mail

In an office IVM needs to decide who the call was for (and which mailbox to use). In a very simple setup the IVM could play a menu and let the caller select. But normally the PBX can send the intended extension to IVM.

Most PBXs can be programmed to send a DTMF dial string (inbound signaling) when the IVM picks up the call. This string of digits is dialed within a short time after answering. You need to find the format of this string in the PBX manual.

Once you know the format of the dial string:

1. Under the Key Response section of the OGM Properties select "Data-Entry".
2. In the maximum digits field enter the number of digits the PBX will send.
3. Tick the "Allow # in data entry" field.
4. Tick the "Use special digits mapping function".
5. Click Settings button next to it. In the box next to "Advanced parsing dial string" enter the dial string in the form XXXX111XXX where 1 corresponds to the intended extension number digits and X are digits to be ignored. In the box to the left of 1 enter mailboxno (all one word all lower case).
6. On the Message tab of OGM Properties next to "Then" select 'Leave Message for Mailbox' and type: MailBox%mailboxno%

If your PBX redirects a call meant for extension 123 it will leave it in MailBox123. You can change the settings of the "Default" mailbox if required.

On some PBXs you can also dial a string to turn off or on a message waiting light. To do this, use the "Mailbox Message Notification" options of MailBox properties.

AutoAttendant - (Menu + Transfer)

For auto-attendant and transferring calls the most important thing is that your PBX allows you to transfer calls with a 'hook flash' dial sequence. Check the manual and then see Transferring Calls for how to setup for call transfer.

The biggest source of problems is the hook flash time (there is no international standard and different PBXs use different times). If IVM takes too long the PBX thinks it has hung up. If it is too short nothing is transferred. Check the flash time for your PBX, and the driver settings for your telephony card. They must match.