Subject: Dgit map clarifications and queries

From: Kushanava Laha <[email-masked]>
Date: Tue, 8 Feb 2000 12:46:35 +0530

Hi Tom,
     This is with reference to the digitmap changes as exchanged in
the earlier mails viz. "Issue score card", "Updates submitted to ITU based
on Issue score card" and "More digitmap fixes dtd. 02/04/2000".
     I list down below some points - a few are queries (q) and the rest
clarifications (c)

1.  Short timer modifier does not explicitly appear in a digitmap string (c)

2. The short timer is implicit. It is started only when there is a '.' (DOT)
encountered
      OR when a pattern has matched but there is a possibility of an alternate
match if more
      digits arrive within the timeout. (c)

3. Only 'L' modifiers can appear in a digit string and if it appears then it
overrides the
     default interdigit timer for the digit position for which it appears. For
subsequent
     digits till the modifier appears again the default interdigit timer is
applicable.
     e.g 123L45 implies that only between 3 & 4 'L' timer is to be started and
for the rest
     it is the default interdigit timer.(q)

4. By a default interdigit timer I mean the timer which is started by the Media
Gateway
     if it can determine that atleast one more digit is needed for a digit
string to match any
     of the allowed patterns in the digit map. But in an earlier mail you have
mentioned that
     this default interdigit timer is the Long Duration timer "L". Then what is
the use of explicitly
     including an 'L' in the digit string ? Isn't it implicit ? Or is it used to
override a short timer ? (q)

5. Section 7.1.14, para 5 describes the 'L' timer as "placed in front ........."
which suggests that
     'L' modifiers dictate  the validity of the duration of the digit following
the modifier to be atleast
     equal to the long-duration threshold and is not applicable for subsequent
digits. This is not
     the same as an interdigit timer. Then what is 'L' ? Is it the interdigit
timer or the digit duration timer ? (q)

6. Given a digit map "123|1234" if the user dials 1235 then is 123 to be
reported through the digit
    completion event? (q)

7. The implication of a "." (DOT) is an indefinite expectation of the digit
preceding the "." within the
     short timer duration. It makes sense then if "." appears after an "x" but
what practical meaning
     does say "7." convey - which is nothing but an indefinite expectation of
"7"s and "7"s only ? (q)

8.  With reference to an example stated by you , in case of DTMF dialing "x.F"
means expecting an
     arbitrary number of digits from 0 to 9 terminated by # and a long timer is
to be started after the
     first digit. As per rule of starting timers it should have been the short
timer because of the presence
     of a ".", then why a long timer ?
     Secondly, what happens on timer expiry and no digits or # being dialed by
the user ? Should MG
     wait infinitely for the # to come or should it report the collected digits
in digit completion event stating
     that # was not received or should the digit collection procedure be
abandoned ? (q)

9. With respect to the same example, "it has been stated that "x.F" and "x."
convey the same meaning
    except for the timer issue. In the case of "x." timer to be started is the
short timer. Other than the confusion on
    the timer to be started issue as conveyed in point 8, a # in this case is
also expected though it is not explicit
    and the rules also don't talk of such things. It is confusing in the sense
that for digit collection other than
    DTMF, where # is not expected the case of "x." becomes indistinguishable.(q)

Regards,
Kushanava Laha,
Hughes Software Systems,
India

---

From: Tom-PT Taylor <[email-masked]>
Date: Thu, 10 Feb 2000 02:27:03 -0600

Answers below.

> -----Original Message-----
> From: Kushanava Laha [SMTP:[email-masked]]
> Sent: Tuesday, February 08, 2000 2:17 AM
> To:   [email-masked]
> Subject:      Dgit map clarifications and queries
>
> Hi Tom,
        [[TomT]]  Neither short nor long timer modifier appears.  The "L" in
the digit map string is for something else entirely (tone duration).

>       digits arrive within the timeout. (c)
        [[TomT]]  Correct

>      it is the default interdigit timer.(q)
        [[TomT]]  No -- "L" means duration of following event matters,
nothing to do with inter-event timing.

> override a short timer ? (q)
        [[TomT]]  See above.  Timing is always implicit.

> 5. Section 7.1.14, para 5 describes the 'L' timer as "placed in front
        [[TomT]]  Digit duration timer, for the one digit position following
it.

> reported through the digit
        [[TomT]]  123 plus the extra event 5, with termination method FM
(per the dd/ce definition in annex E)

>      does say "7." convey - which is nothing but an indefinite expectation
        [[TomT]]  That's correct.

>      of a ".", then why a long timer ?
        [[TomT]]  I agree with you -- it should be a short timer.

>      that # was not received or should the digit collection procedure be
        [[TomT]]  Report completion showing the digit string collected,
presumably no extra digit, and termination method PM (partial match).

>     except for the timer issue.
        [[TomT]]
         I deny that.  If you specify x. and a # is dialled, the result will
be reported as full match (FM) with extra digit (F).  The # represents a
departure from the pattern and immediately triggers the completion event.
You get the same immediate report and inter-event timing if you specify x.F,
but it will be reported with the F included in the dial string, no extra
event, and termination method UA (unambiguous match).  I would imagine that
the first result would be the more useful, since it automatically extracts
the irrelevant # event.

> In the case of "x." timer to be started is the
> short timer.
        [[TomT]]  Wherever a dot appears, it creates a situation of
ambiguity mandating use of the short timer.
> Other than the confusion on