Ok, this is something that has to do with the way PBXs are operating.
Usually a phone is a combination of two distinct functions: call-control and ACD control.
Many of PBXs are made to be used both in the office and in the call center. In the office, you just use the phone to make and receive calls and phone is considered a means of getting in touch with the client. For callcenter PBX is much more than that - it IS the business and people get paid to support it by answering the calls. So, it is necessary not only to track the calls, but also what people do regarding this call. This is where position comes in. This is an additional feature that is added to PBX and allows PBX administrators to track what operator is doing and why. Login/Logout, Ready/NotReady, ACW, etc all of the agent statuses are signalled via ACD Position. The calls themselves are controlled via Extension.
Since Extension can only be on-call or off-call, it is impossible to tell if operator is ready to receive the next call after he hang up or not, so call queuing is also implemented with the combination of ACD Queues and ACD Positions. A call that has arrived into a queue will be sent to the agent that is READY. And since ACD Position is the one that is signalling that the operator is ready, the call is send to ACD Position.
So, extensions are for outbound calls and direct calls where the other user dialled directly the number of this operator. URS also sends the calls to extension.
ACD Position is to track operator status and to receive ONLY calls from the ACD queue that operator is logged in.
For PBX Extension and ACD Position come as two lines on the same phone, but Genesys does not know which extension comes with which position, since it cannot see the actual phones but only the lines. This is why Place is so important. This is how you tell Genesys which ACD Position comes with which Extension. Without this, you would be logged out in ACD Position, but since Extension is not on call, URS might think that operator is free and send the call to it. And you will end up with a ringing phone who no one will answer. And then you find out that your PBX guy messed up RONA and then your caller complains that he was listening to ringing tone for three hours (yes, there are people like this) and you end up giving him an year-worth of free rust-proofing on his Yugo.
I hope it makes it clear
