Tata Docomo was the first operator in the country to offer truly unlimited voice calling plans for a nominal monthly rental. Initially they were great, but as the number of users increased, they started making certain amendments to the pack details. Conference calling suffered a similar hit as well. It was initially offered free with the unlimited plans, but was later dropped.
Conference Calls Not Allowed in All Unlimited Plans
It seems that the 3-way conferencing limitation is not bound to only the ₹899 plan, but also their higher priced plans such as the ₹1299 unlimited Plan. The probable cause behind implementing this limitation might be the users abusing the service by calling multiple parties and staying in call for long durations. Whatever the cause be, the reality is that conferencing is not allowed and Tata Docomo openly accepts the same.
Is there any alternative?
For sure! Reliance also offers similar unlimited calling plans and as of writing this post, they do allow making conference calls. These plans are priced almost the same as that of Docomo, but do make sure that Reliance has a proper coverage in your area before making a jump from Docomo to Reliance.
However, one thing to note is that Reliance only allots 6000 minutes (100 hours) of calling per month under their fair usage policy.