Subject: [SIP] Call Park abd Call Pickup

From: Hong Chen <[email-masked]>
Date: Thu, 27 Jul 2000 13:29:15 -0500

I need helps to understand how to implement CALL Park and Call Pickup
features
by SIP?

Thanks,

Henry

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From: "Jo Hornsby" <[email-masked]>
Date: Fri, 28 Jul 2000 10:35:33 +0100

> features by SIP?

As far as "Call Pickup", I would look up the thread
"on directed pick up service" in the archives; it caused a
small staircase at the beginning of this month.

I'll have a bash at "Call Park".  If I remember it rightly (I'm
harking back to my days working in a supermarket, and
retrospectively injecting my small amount of telephony switch
knowledge, so please forgive me), it's when a call is
(temporarily) terminated at some logical point in the switch,
right?  And this call can then be picked-up from an arbitrary
'phone by dialling a feature code, or whatever?

Modelling similarly, I guess it could be achieved using a
combination of directed pickup and REFER (transfer); call
is parked by magic of REFER, and is left ringing on some logical
UA somewhere; call is subsequently retrieved by issuing a
REGISTER for that logical UA from the pickup point.

Note that I'm sure there are far more elegant and sophisticated
ways of doing these things within SIP...especially once one has a
rich interface.  I would think that these sort of mappings
only really need to be applied in dumb 'phone environments.

Cheers,

 - Jo.

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From: Rohan Mahy <[email-masked]>
Date: Fri, 28 Jul 2000 10:43:48 -0700

Hi,

I think Pickup was well described in a previous thread.  If you wanted to 
do traditional Park things, I can think of 4 variations (with or without 
music, and with or without Revert)

I think I am suggesting essentially the same thing as Jo did.  You can read 
both and see if either make sense to you.

A and B have an existing session.

B sends a REFER to A, which redirects their session to

         <sip:[email-masked]>

the forwarding logic for "so-queue-me"  would return a 182 call queued.  If 
desired, music/announcements could be played using 183 with Session: media.
To retrieve the call just REGISTER "park-12" with a short expires timer.

If revert was desired, the forwarding logic would eventually give up and 
forward the INVITE to the parker or an attendant.

hope this helps.  thanks,
-rohan

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From: Henning Schulzrinne <[email-masked]>
Date: Sat, 29 Jul 2000 22:09:57 -0400

I think this may be a feature where we should ask "what do we want to
accomplish from a user perspective", not "how do we replicate a feature
called Call Park/Pickup". In particular, is this used for some unknown
party to pick up, after the clerk hollers into the store PA system
"whoever is in the adult diaper aisle, call on line 1?". If you know who
you're addressing, with personal mobility, you can just transfer or
redirect the call, without the intermediate parking.

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From: "Brian F. G. Bidulock" <[email-masked]>
Date: Sat, 29 Jul 2000 21:33:54 -0500

Henning,

If I recall correctly the purpose of Call Park and Call Pickup
was to "replicate a feature" of keysets (those ones with the
line 1, line 2 lit pushbuttons): that is, the ability to place a
call on hold and pick it up on another set, or place a call on
hold and holler across the room to someone on the phone with
another set (or buzz their Intercom line).  When we got those
Digital Centrex kind of phones, Call Park and Call Pickup tried
to replace these features: people who liked keysets would just
not purchase anything else otherwise.

With these features, we could park a call against someone's
number and when they hung up the phone it would ring through.
If it wasn't answered for some time, it would come back to the
"parker".  This was intuitively similar to placing the call on
hold an buzzing a person's intercom number.

Call pickup was so that one could place a call on hold and then
pick it up from another line by dialing feature code.  This was
helpful for moving around the office when a person was used to
keysets where one could place the call on line 3 on hold and
then just pickup another set and punch line 3.

Even though the features are provided on modern Digital Centrex
and PABX's, I don't know of many people that even use them: they
are too complicated and were only really intuitive if you had
been working with keysets for a long time.  You have to remember
that we didn't have voice mail, call waiting, or mobile (even
cordless) phones, which are far more popular today.  These
features had more to do with physically moving around the office
or running calls for a group of people with a single group
secretary.

The need that went with these features have been satisfied by other
means and are largely deprecated.  Far more sophisticated capabilities
has been provided with modern call centre approaches.

Henning Schulzrinne wrote:                (Sat, 29 Jul 2000 22:09:57)
> accomplish from a user perspective", not "how do we replicate a
> feature called Call Park/Pickup". In particular, is this used for some
> unknown party to pick up, after the clerk hollers into the store PA
> system "whoever is in the adult diaper aisle, call on line 1?". If you
> know who you're addressing, with personal mobility, you can just
> transfer or redirect the call, without the intermediate parking.

-- 
Brian F. G. Bidulock
[email-masked]

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From: Jonathan Rosenberg <[email-masked]>
Date: Sat, 29 Jul 2000 23:05:20 -0400

> To retrieve the call just REGISTER "park-12" with a short expires timer.

How would B know which park address to use? The park address has to be
unique, and also has to
be something the person picking up would know to use. My suggestion -
instead of "12", you
would use the URL or address of the host which performed the park:

<sip:[email-masked]>

This way, if I want to pick up a call parked by B, I know I would have
to try to register the address above. You could then define pickup
groups by authenticating REGISTER, and only allowing people to register
for park-foo if they are in a group allowed to pickup calls parked by
foo.

-Jonathan R.

-- 
Jonathan D. Rosenberg                       72 Eagle Rock Ave.
Chief Scientist                             First Floor
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[email-masked]                     FAX:   (973) 952-5050
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