Field	Description
`calledaddr`	The called number. Also referred to as the Direct Inward Dial (DID) number.
`callingaddr`	The calling number (if available). Also referred to as the Automatic Number Identification (ANI) number.
`usercategory`	The call category.

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Chapter 18

MF Socotel Protocol

18.1 Introduction

: 18.1.1 Signaling Overview

18.2 Parameters

: 18.2.1 Editable Parameters
: 18.2.2 Non-editable Parameters

18.3 Special TCP Behavior

: 18.3.1 Inbound Calls: Retrieving Digits All at Once
: 18.3.2 Inbound Calls: Retrieving Digits One at a Time
: 18.3.3 Outbound Calls: Digit Format

18.1 Introduction

This chapter provides the following information: · Overview of the MF Socotel (MFS) protocol concepts · MFS TCP parameters · Operations that are specific to the MFS protocol within the framework of Natural Call Control.
The MFS TCP implements the Spanish National CAS Protocol, as specified by the Royal Decree 1562/1992, and amended by the Order 5309 of the Ministry of Industry, February 23, 1998.

18.1.1 Signaling Overview

Although E1 Channel Associated Signaling (CAS) framing supports 4 signaling bits per direction, only one of them is used in general for the MFS line signaling.
The signaling channels supporting the MFS line signaling protocol are referred to as Af in the forward direction, and Ab in the backward direction. The forward channel indicates the condition of the outbound switch equipment and reflects the condition of the calling party's line. The backward channel indicates the condition of the called party's line (the inbound equipment).
The Bb bit might also be used, but only to convey billing pulses to the outbound equipment. The Bf bit is never used instead, and is always set to 1. The C and D bits are set to 0 and 1 respectively for both directions.
The following table illustrates the signaling states of a typical call. State Outbound AfBf Direction Inbound AbBb Idle 11 \xdf 11 Seizure 01 11 Seizure Acknowledged 01 \xdf 01 Here the inbound side requests the address information, and the outbound sends the data. This is accomplished by an in-band compelled sequence. The inbound side completes the compelled sequence by accepting or rejecting the call, using the last backward compelled tone. If the call has been accepted, the inbound side plays a ring tone on the line, and then signals that the call has been answered by setting the Ab bit to 0 Ringing 01 \xdf 01 Answer - conversation state 01 \xdf 11 If the inbound side rejects the call instead, the outbound side clears forward, by setting the Af bit to 1. The inbound side goes back to idle, by setting the Ab bit to 1 as well Clear forward 11 01 Idle 11 \xdf 11 During conversation the outbound protocol can receive billing pulses, to signal that a unit of cost has been billed to the call. The bit used to carry a billing pulse is the Bb bit. Answer - conversation state 01 \xdf 11 Billing pulses 01 \xdf 10 Answer - conversation state 01 \xdf 11 Depending on which of the sides hangs up the call first, we have a clear back signal, or a clear forward signal. There is then a period of time in which the inbound side holds a release guard state, which is the same as clear back but happens when the outbound side is already in the idle state. Idle follows. Inbound hangs up first: Clear back 01 \xdf 01 Clear forward / release guard 11 01 Idle 11 \xdf 11 Outbound hangs up first: Clear forward 11 11 Release guard 11 \xdf 01 Idle 11 \xdf 11
Register signaling is accomplished by a MF Socotel compelled scheme. This is different from the R2 (CCITT Recommendation 441) compelled sequence. The basic concept is the following:
At the beginning of the compelled sequence, the inbound equipment plays a request tone (usually "send all digits").This is a MF tone. The outbound responds with a pure tone (1900 Hz), which has no other meaning than acknowledging the request form inbound.
Then the sequence switches side: the outbound equipment plays MF tones (the address of the called terminal), while the inbound equipment plays acknowledgment tones.
When all the digits have been delivered, the sequence switches side again, and the inbound equipment accepts or rejects the call, depending on the state of the called terminal.
This kind of compelled sequence can only work if a very strict numbering scheme is in use in the network. In fact, the inbound side must know exactly the number of DID and ANI digits to expect in order to allow the compelled sequence to take place correctly. In Spain all telephone number are nine digits long. All extensions reachable through the national CAS protocol are five digits long. So: · The expected number of DID is always five · The number of DID while dialing out is always nine · The expected number of ANI is always nine

State	Outbound AfBf	Direction	Inbound AbBb
Idle	11	\xdf	11
Seizure	01		11
Seizure Acknowledged	01	\xdf	01
Here the inbound side requests the address information, and the outbound sends the data. This is accomplished by an in-band compelled sequence. The inbound side completes the compelled sequence by accepting or rejecting the call, using the last backward compelled tone. If the call has been accepted, the inbound side plays a ring tone on the line, and then signals that the call has been answered by setting the Ab bit to 0
Ringing	01	\xdf	01
Answer - conversation state	01	\xdf	11
If the inbound side rejects the call instead, the outbound side clears forward, by setting the Af bit to 1. The inbound side goes back to idle, by setting the Ab bit to 1 as well
Clear forward	11		01
Idle	11	\xdf	11
During conversation the outbound protocol can receive billing pulses, to signal that a unit of cost has been billed to the call. The bit used to carry a billing pulse is the Bb bit.
Answer - conversation state	01	\xdf	11
Billing pulses	01	\xdf	10
Answer - conversation state	01	\xdf	11
Depending on which of the sides hangs up the call first, we have a clear back signal, or a clear forward signal. There is then a period of time in which the inbound side holds a release guard state, which is the same as clear back but happens when the outbound side is already in the idle state. Idle follows.
Inbound hangs up first: Clear back	01	\xdf	01
Clear forward / release guard	11		01
Idle	11	\xdf	11
Outbound hangs up first: Clear forward	11		11
Release guard	11	\xdf	01
Idle	11	\xdf	11

18.2 Parameters

The MFS TCP is programmed by the parameters described in the following sections. Caution: Most of the parameters that follow are signaling-specific: changing their value would not only invalidate any approval certificate for the used board, but would also most likely cause the board to malfunction. These parameters are described here for reference purposes only.
Other parameters program the interaction the TCP has with the host, or act on features not regulated or that can change from switch to switch within the same network. These are changeable, and indeed, the application developer is often asked to do so.

Caution:	Most of the parameters that follow are signaling-specific: changing their value would not only invalidate any approval certificate for the used board, but would also most likely cause the board to malfunction. These parameters are described here for reference purposes only.

18.2.1 Editable Parameters

Users can modify the following ADI.MFS parameters within the limitations provided in the Description field: Field Name Type/Unit Default Description DIDnumber number 5 Inbound: Specifies the number of incoming DID digits to expect. In SPain, the PSTN will always provide five DID digits. ANInumber number 9 Inbound: Specifies the number of incoming ANI digits to expect. Set to 0 for no ANI collection. Possible values are 0 or 9. RTCdigitnumber number 9 Outbound: Specifies the number of digits that has to be provided to the network (RTC=Rede Telefonica Conmutada). Spain has a fixed 9 digit scheme which cannot be changed. optionflags mask 0x1 Flags controlling optional TCP behavior: · bit 0 (&0x1): Controls playing busy tone after rejecting a call. If 0, play the tone, if 1, don't. Default: 1. · bit 1 (& 0x2): Controls playing cleardown tone after clearing back a call. If 0, don't play the tone, if 1, play. · bit 2 (& 0x4): If set, the trunk is inbound only. · bit 3 (& 0x8): If set, the trunk is outbound only. · bit 4 (& 0x10): If 1, inbound requests the ANI digits first, then the DID digits. If 0, the other way around. · bit 5 (& 0x20): Controls the frequency of the compelled acknowledgment tone. The current specifications are for a 1900 Hz tone, but some switches might still need a 1700 Hz tone (old specifications). If the bit is 0 (default), the tone is 1900 Hz; if it's 1, the tone is 1700 Hz. debugmask mask 0x0 Specifies what trace messages are generated (run agtrace 1000 or higher to see them): · 0x01: Show all states as they are entered · 0x02: Show sent and received digits · 0x04: Show signaling bits · 0x08: Print a description of timeout- related errors These values can be ORed for cumulative effect.

Field Name	Type/Unit	Default	Description
`DIDnumber`	number	`5`	Inbound: Specifies the number of incoming DID digits to expect. In SPain, the PSTN will always provide five DID digits.
`ANInumber`	number	`9`	Inbound: Specifies the number of incoming ANI digits to expect. Set to `0` for no ANI collection. Possible values are 0 or 9.
`RTCdigitnumber`	number	`9`	Outbound: Specifies the number of digits that has to be provided to the network (RTC=Rede Telefonica Conmutada). Spain has a fixed 9 digit scheme which cannot be changed.
`optionflags`	mask	`0x1`	Flags controlling optional TCP behavior: · `bit 0 (&0x1)`: Controls playing busy tone after rejecting a call. If 0, play the tone, if 1, don't. Default: 1. · bit 1 (& 0x2): Controls playing cleardown tone after clearing back a call. If 0, don't play the tone, if 1, play. · bit 2 (& 0x4): If set, the trunk is inbound only. · bit 3 (& 0x8): If set, the trunk is outbound only. · bit 4 (& 0x10): If 1, inbound requests the ANI digits first, then the DID digits. If 0, the other way around. · bit 5 (& 0x20): Controls the frequency of the compelled acknowledgment tone. The current specifications are for a 1900 Hz tone, but some switches might still need a 1700 Hz tone (old specifications). If the bit is 0 (default), the tone is 1900 Hz; if it's 1, the tone is 1700 Hz.
`debugmask`	mask	`0x0`	Specifies what trace messages are generated (run `agtrace` 1000 or higher to see them): · `0x01`: Show all states as they are entered · `0x02`: Show sent and received digits · `0x04`: Show signaling bits · `0x08`: Print a description of timeout- related errors These values can be ORed for cumulative effect.

18.2.2 Non-editable Parameters

The following ADI.MFS parameters are country- or network-specific, and cannot be modified. Field Name Unit Description Example Compelled Timers timerT1 ms Specifies Timer T1, maximum time between the line seized and the first request from inbound. 10000 timerT2 ms Specifies Timer T2, maximum time between the end of a confirmation tone and the beginning of the next information tone. 20000 timerT3 ms Specifies Timer T3, maximum time of a whole compelled cycle, starting when a information tone is started and ending when the corresponding confirmation tone stops (from the point of view of the party sending the information). 5000 timerT4 ms Specifies Timer T4, maximum time of a whole compelled cycle, starting when a information tone starts and ending when the corresponding confirmation is stopped (from the point of view of the party sending the confirmation). 5000 timerT5 count (s) Specifies Timer T5, overall maximum duration of the compelled sequence. 90 timerT6 ms Specifies Timer T6, minimum time between end of transmission of a confirmation signal and beginning of transmission of the next information tone. 40 Line signaling timers bitsqualtime ms Qualification time for bits signals. 10 releaseguardtime ms Minimum time of the release guard pulse (from inbound). 150 clearbacktime1 ms Release guard recognition time if inbound clears first. 100 clearbacktime2 ms Release guard recognition time if outbound clears first. 200 answertime count (s) Time in seconds the outbound waits for the inbound to answer, after the end of register signaling if the call has been accepted. 60 Compelled tones tonesPSTNgroupA internal Tones sent by the PSTN in Group A, from least to most significant: · Send all DID digits (`d'). · Send all ANI digits (`c'). · Switch to Group II (`8'). · Send the call category (`3'). 0x38cd toneserror internal Tones sent to signify various error conditions. From least to most significant: · Congestion in Group A (`a'). · ANI not available (`f'). · Congestion in Group B (`2'). 0x02fa tonesgroupB internal Backward Group B tones (in either direction). From least to most significant: · Call accepted, phone is ringing (`1'). · Line busy (`4'). · Unallocated number (`8'). · End of selection - line status unknown - call progress tone follows (`9'). 0x9841 tonesCPEgroupA internal Backward Group A tones from the CPE. From least to most significant: · Send Digit Group BC (`4'). · Send all ANI digits (`2'). · Switchover to Group B (`8'). 0x0824 tonesmiscellaneous internal Miscellaneous tones. From least to most significant: · Default outbound category (`2'): external call, billing by line. 0x0002 compelledtonelevel IDU Amplitude of compelled tones. 300 Call progress tones (inbound ring / busy control) ringfreq Hz Specifies the ring tone frequency. 425 ringontime ms Specifies the time the ring tone is on in a ring cycle. 1500 ringofftime ms Specifies the time the ring tone is off in a ring cycle. 3000 ringtonelevel IDU Specifies the amplitude of ring tones. 330 busyfreq Hz Specifies the busy tone frequency. 425 busyontime ms Specifies the time the busy tone is on in a busy cycle. 200 busyofftime ms Relevant to inbound protocols. Specifies the time the busy tone is off in a busy cycle. 200 busytonelevel IDU Specifies the amplitude of busy tones. 330 congestiontones count Number of congestion tones in a fast busy cycle. 3 congestionontime ms Time the congestion tone is on. 200 congestionofftime1 ms First off-time for the congestion tone. 200 congestionofftime2 ms Second off-time for the congestion tone. 600 Timers related to the AG Quad boards resource management. resourcegettimes internal This parameter addresses a special need of protocols running on a AG Quad board with resource management enabled. If this is the case, for certain operations it is necessary to acquire a resource from a resource pool on the board. The parameter defines to timeouts after which the operation is aborted if a resource is not available. (This is a unlikely.) Low byte: time to wait for resource before placing a call (15 s) High byte: time to wait for resource when a resource is needed by inbound to release a call (e.g. to play a cleardown tone) (10 s) 0x0a0f

Field Name	Unit		Description	Example
Compelled Timers
`timerT1`	ms	Specifies Timer T1, maximum time between the line seized and the first request from inbound.	`10000`
`timerT2`	ms	Specifies Timer T2, maximum time between the end of a confirmation tone and the beginning of the next information tone.	`20000`
`timerT3`	ms	Specifies Timer T3, maximum time of a whole compelled cycle, starting when a information tone is started and ending when the corresponding confirmation tone stops (from the point of view of the party sending the information).	`5000`
`timerT4`	ms	Specifies Timer T4, maximum time of a whole compelled cycle, starting when a information tone starts and ending when the corresponding confirmation is stopped (from the point of view of the party sending the confirmation).	`5000`
`timerT5`	count (s)	Specifies Timer T5, overall maximum duration of the compelled sequence.	`90`
`timerT6`	ms	Specifies Timer T6, minimum time between end of transmission of a confirmation signal and beginning of transmission of the next information tone.	`40`
Line signaling timers
`bitsqualtime`	ms	Qualification time for bits signals.	`10`
`releaseguardtime`	ms	Minimum time of the release guard pulse (from inbound).	`150`
`clearbacktime1`	ms	Release guard recognition time if inbound clears first.	`100`
`clearbacktime2`	ms	Release guard recognition time if outbound clears first.	`200`
`answertime`	count (s)	Time in seconds the outbound waits for the inbound to answer, after the end of register signaling if the call has been accepted.	`60`
Compelled tones
`tonesPSTNgroupA`	internal	Tones sent by the PSTN in Group A, from least to most significant: · Send all DID digits (`d'). · Send all ANI digits (`c'). · Switch to Group II (`8'). · Send the call category (`3').	`0x38cd`
`toneserror`	internal	Tones sent to signify various error conditions. From least to most significant: · Congestion in Group A (`a'). · ANI not available (`f'). · Congestion in Group B (`2').	`0x02fa`
`tonesgroupB`	internal	Backward Group B tones (in either direction). From least to most significant: · Call accepted, phone is ringing (`1'). · Line busy (`4'). · Unallocated number (`8'). · End of selection - line status unknown - call progress tone follows (`9').	`0x9841`
`tonesCPEgroupA`	internal	Backward Group A tones from the CPE. From least to most significant: · Send Digit Group BC (`4'). · Send all ANI digits (`2'). · Switchover to Group B (`8').	`0x0824`
`tonesmiscellaneous`	internal	Miscellaneous tones. From least to most significant: · Default outbound category (`2'): external call, billing by line.	`0x0002`
`compelledtonelevel`	IDU	Amplitude of compelled tones.	`300`
Call progress tones (inbound ring / busy control)
`ringfreq`	Hz	Specifies the ring tone frequency.	`425`
`ringontime`	ms	Specifies the time the ring tone is on in a ring cycle.	`1500`
`ringofftime`	ms	Specifies the time the ring tone is off in a ring cycle.	`3000`
`ringtonelevel`	IDU	Specifies the amplitude of ring tones.	`330`
`busyfreq`	Hz	Specifies the busy tone frequency.	`425`
`busyontime`	ms	Specifies the time the busy tone is on in a busy cycle.	`200`
`busyofftime`	ms	Relevant to inbound protocols. Specifies the time the busy tone is off in a busy cycle.	`200`
`busytonelevel`	IDU	Specifies the amplitude of busy tones.	`330`
`congestiontones`	count	Number of congestion tones in a fast busy cycle.	`3`
`congestionontime`	ms	Time the congestion tone is on.	`200`
`congestionofftime1`	ms	First off-time for the congestion tone.	`200`
`congestionofftime2`	ms	Second off-time for the congestion tone.	`600`
Timers related to the AG Quad boards resource management.
`resourcegettimes`	internal	This parameter addresses a special need of protocols running on a AG Quad board with resource management enabled. If this is the case, for certain operations it is necessary to acquire a resource from a resource pool on the board. The parameter defines to timeouts after which the operation is aborted if a resource is not available. (This is a unlikely.) Low byte: time to wait for resource before placing a call (15 s) High byte: time to wait for resource when a resource is needed by inbound to release a call (e.g. to play a cleardown tone) (10 s)	`0x0a0f`

18.3 Special TCP Behavior

The following sections describe operations that are specific to the MFS protocol within the framework of Natural Call Control.

18.3.1 Inbound Calls: Retrieving Digits All at Once

For MFS, after ADIEVN_INCOMING_CALL is received, the following fields in the ADI_CALL_STATUS structure contain the received digits: Field Description calledaddr The called number. Also referred to as the Direct Inward Dial (DID) number. callingaddr The calling number (if available). Also referred to as the Automatic Number Identification (ANI) number. usercategory The call category.
Several entries in the TCP parameter file affect the way the MFS TCP accepts and processes digits. MFS Parameter Description ADI.MFS.DIDnumber This parameter determines the number of Direct Inward Dial (DID) digits the TCP should expect from the calling party. Default is 5. ADI.MFS.ANInumber This parameter determines the number of Automatic Number Identification (ANI) digits the TCP should expect. Default for the Spanish National Numbering Plan is 9. This value should not be changed, unless it is set to zero; in this case no ANI digits are collected. ADI.MFS.optionflags, bit 4 (& 0x10) This bit determines if the inbound part of the MFS TCP requests the ANI digits or the DID digits first. Signaling-wise, there is no difference between the two options, both being equally supported by the specifications.
Refer to Chapter 5 for instructions about loading parameter files.

MFS Parameter	Description
`ADI.MFS.DIDnumber`	This parameter determines the number of Direct Inward Dial (DID) digits the TCP should expect from the calling party. Default is 5.
`ADI.MFS.ANInumber`	This parameter determines the number of Automatic Number Identification (ANI) digits the TCP should expect. Default for the Spanish National Numbering Plan is 9. This value should not be changed, unless it is set to zero; in this case no ANI digits are collected.
`ADI.MFS.optionflags,` `bit 4 (& 0x10)`	This bit determines if the inbound part of the MFS TCP requests the ANI digits or the DID digits first. Signaling-wise, there is no difference between the two options, both being equally supported by the specifications.

18.3.2 Inbound Calls: Retrieving Digits One at a Time

For MFS, the digits appear in the following format:
d1 d2 d3 d4 d5 # a1 a2 a3 a9 if receiving DID digits first.
a1 a2 a3 a9 # d1 d2 d3 d4 d5 if receiving ANI digits first.
d1 d2 d3 d4 d5 if not receiving ANI digits.
where: d1d5 DID digits received (always 5 in Spain for a CPE) a1 am ANI digits received. # NMS separator symbol.

d1d5	DID digits received (always 5 in Spain for a CPE)
a1 am	ANI digits received.
#	NMS separator symbol.

18.3.3 Outbound Calls: Digit Format

The MFS TCPs expect the digit string to be formatted as follows:
# c a1 . am # d1 dn
where: c User category of the call a1 am ANI digits (the address of the calling party). d1dn DID digits (the address of the called party). # NMS separator symbol.
User category and ANIs can be omitted if the connection does not require them to be present. If these are omitted, the digit string should be formatted as follows:
d1 dn Note: In this case, the default call category is used.

c	User category of the call
a1 am	ANI digits (the address of the calling party).
d1dn	DID digits (the address of the called party).
#	NMS separator symbol.

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