Mikael Andersson  -- <> wrote on den 27 april 2004 13:40:

> 
> I guess nobody has tried that ?
> 
> Here in Sweden we don't have FSK Callerid from our Telco. I guess
> that goes for all of Scandinavia. 
> 
> I am not a programmer, but I wonder, is it hard to fix a driver for
> the wildcard x100p that can detect DTMF callerid ? 
> 
> /Mike
> 
> 

I'm replying to myself here just to add som technical details on the Swedish Telco CID 
system:

Soorry if the mail is long.

This is how CallerID is sent to the customer from the telcos in Sweden. Is it possible 
to get the x100p to understand this ?



-----snip----

DEFINITIONS

Z interface is a term used in this document for all types of analogue 2-wire 
interfaces at the network operator side of analogue subscriber lines delivering the 
PSTN service. The Z interface can be located in local exchanges (LEs), remote 
concentrators or multiplexors or in network terminating units (NTs) or terminal 
adaptors (TAs) located at the userÂs premises.

An international number consists of a Country Code (CC) and a National (Significant) 
Number (N(S)N). An example: 46 8 7132920, where CC = 46 and N(S)N = 8 7132920.

A national (significant) number consists of a trunk code (TC) and a subscriber number 
(SN) e.g. N(S)N=8 7132920, where TC=8 and SN=7132920. An area code consists of a 
national prefix (0) and the trunk code (TC).

The Calling Number is the information designating the calling user who initiated the 
call.

The Redirecting Number is the information sent in the forward direction when a call is 
diverted, indicating the diverting user from which the call was diverted or, in case 
of multiple diversions, the diverting user from which the call was last diverted.

A restricted number is a number to be restricted from presentation. The reasons for 
restricting numbers are as follows:

â the calling user (and/or the diverting user) has required that his number shall 
not be presented.

â the calling user has invoked a number presentation restriction on a call-by-call 
basis

â other reasons.

Symbols according to table 1 are used in the protocol for information transfer in 
clause 4 and 5.



Table 1

A       Start code for a Calling Number (DTMF character âAâ ) 
B       Start code for an information code (DTMF character âBâ ) 
C       Stop code (DTMF character âCâ ) 
D       Start code for a Redirecting Number (DTMF character âDâ ) 
Sn      DTMF digits â0â to â9â 
-       Inter-digit pause between all DTMF digits/characters 
N       Integer < 15 
S1-S2...Sn 0 + the national significant number in case of national call 
00 + the international number in case of international call 
T1-t2 Information code where tn is DTMF digits â0â to â9â


TRANSFER OF NUMBER INFORMATION

The user number S1S2...Sn shall be sent at the Z interface according to the 
alternatives below. Symbols are defined in table 1.
For an ordinary (non-diverted) call, 1a or 1b shall apply.
For a diverted call, 2a or 2b shall apply.

1a) For an ordinary call, the Calling Number shall be transferred as
D-S1-S2...Sn-C

1b) For an ordinary call, the Calling Number shall be transferred as
A-S1-S2...Sn-C

2a) For a diverted call (see figure 1), the Redirecting Number (b) shall be 
transferred as D-S1-S2...Sn-C

2b) For a diverted call (see figure 1), the Calling Number (a) and the Redirecting 
Number (b) shall be transferred as A-S1-S2...Sn-D-S1-S2...Sn-C


NO TRANSFER OF NUMBER INFORMATION

In two cases defined below, the number information according to clause 4 shall be 
replaced by an information code t1-t2. 

1) If no number is available, the information code shall be transferred as
B-t1-t2-C where t1-t2 = 0-0

A restricted number (see definition in clause 3) shall not be presented and the 
information code shall be transferred as
B-t1-t2-C where t1-t2 = 1-0

Normal call set-up

(1) The line is in idle state and the userÂs terminal equipment is on-hook. Idle 
polarity at the Z interface shall be 0 V (earth) at a-wire and â48 to â52V DC at 
b-wire.

When number information shall be sent, the system shall ...

(2) seize the line and perform polarity reversal. The voltage shall be the same as in 
(1) but the polarity shall be reversed.

(3) send number information according to clause 4 or information codes according to 
clause 5. The sending of the information shall start not sooner than 200 ms but not 
later than 1000 ms after the polarity reversal.

(4) perform polarity reversal back to idle polarity as in (1).

(5) send the first ringing signal not sooner than 80 ms after the polarity reversal in 
(4), but not later than 1000 ms after the end of the stop code âCâ.

----------------




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