I've got an email some time ago as well as a reader asking the other day how to make a conference call on the P1i, so here's a simple guide in laymen terms on how to do it:
- Make the call to caller A. Alternatively, accept the incoming call from caller A. Either way have a call going on.
- Now tell caller A to wait.
- Click on 'More' which should be the center option on your current phone interface. Click 'Add Call'.
- Key in caller B's number in to the phone. Click the left button 'Call' and then wait for caller B to connect. Presto - now you have both callers on the line!



it start a second call, then, when i click on start conference call, it say network error ...
Surely there's no way the P1i is able to mux the call on the handset... ergo, this is an operator feature and must be supported by your carrier...
Conferencing can be done by the above steps. But it is an operator feature and must be enabled at their end too.
Hello.
P1i in Polish operator Era GSM.
Conference call is enabled (in operator) but swicthing it on in menu makes an error. Only hanging first call and switching to another is working fine.
Soft: R9H004
I've posted about this on forums few months ago. Seems like not many people use the conferencing on the p1, which is weird. Anyway, I have this same error, and I don't think its an operator/network error, cos T-Mobile supports it, and it works on other phones, just not the p1. After answering the 2nd call, I can't hear the first caller anymore, and have to drop both calls.
Conference calls still work here under R9K009. On the other side Optimobile Uniphone outgoing calls do not work since that upgrade...
....RE: R9K009 -> Optimobile Uniphone post above:
Seems to be a settings issue. The settings used before don't work here any longer. Putting the direct ip addresses in SIP server and outbound proxy server helped to solve the issue here. See also Optimobile forum about this issue.
J
I can confirm Call Conference feature works for Vodafone New Zealand network on firmware R9H004 and R9K009, both on Pre-pay and On-Account.
I had to contact customer service to have it enabled for the pre-pay, but it was already working for the On-account.
SonyEricsson, please get your act together and officially provide R9K009 for NZ, it works fine.
-Rjp.
I can confirm conference calling for R9K009 works with T-Mobile in the US.