# MFS non-editable parameters

The following NCC.X.ADI_MFS parameters are country or network specific, and cannot be modified.

Caution: | Most of the parameters that follow are signaling specific. Changing their value invalidates any approval certificate for the used board and can cause the board to malfunction. These parameters are described here for reference purposes only.

Field | Unit | Default | Description
--- | --- | --- | ---
Compelled timers
timerT1 | ms | 10000 | Specifies Timer T1, maximum time between the line seized and the first request from inbound.
timerT2 | ms | 20000 | Specifies Timer T2, maximum time between the end of a confirmation tone and the beginning of the next information tone.
timerT3 | ms | 5000 | 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).
timerT4 | ms | 5000 | 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).
timerT5 | ms | 90 | Specifies Timer T5, overall maximum duration of the compelled sequence.
timerT6 | ms | 30 | Specifies Timer T6, minimum time between end of transmission of a confirmation signal and beginning of transmission of the next information tone.
Line signaling timers
bitsqualtime | ms | 20 | Qualification time for bits signals.
releaseguardtime | ms | 150 | Minimum time of the release guard pulse (from inbound).
clearbacktime1 | ms | 100 | Release guard recognition time if inbound clears first.
clearbacktime2 | ms | 200 | Release guard recognition time if outbound clears first.
answertime | count | 60 | Time in seconds the outbound waits for the inbound to answer, after the end of register signaling if the call has been accepted.
Compelled tones Tones sent by the PSTN in Group A:
tnGAPSTNsendallDID | mask | 0xD | Send all DID digits (D).
tnGAPSTNsendallANI | mask | 0xC | Send all ANI digits (C).
tnGAPSTNswitchtoG2 | mask | 0x8 | Switch to Group II (8).
tnGAPSTNsendCallCategory | mask | 0x38CD | Send the call category (3).
Tones sent to signify various error conditions:
tnCongestionGroupA | mask | 0xA | Congestion in Group A (A).
tnANInotavailable | mask | 0xF | ANI not available (F).
tnCongestionGroupB | mask | 0x2 | Congestion in Group B (2).
Backward Group B tones (in either direction):
tnGBlinefree | mask | 0x1 | Line free, billing (1).
tnGBlinebusy | mask | 0x4 | Line busy (4).
tnGBunallocatednumber | mask | 0x8 | Unallocated number (8).
tnGBendofselection | mask | 0x9 | End of selection - line status unknown - call progress tone follows (9).
Backward Group A tones from the CPE:
tnGACPEsenddigitGBC | mask | 0x9 | Send Digit Group BC (4).
tnGACPEsendallANI | mask | 0x4 | Send all ANI digits (2).
tnGACPEswitchtoGII | mask | 0x2 | Switchover to Group B (8).
tndefaultoutcategory | mask | 0x8 | Default outbound category (2): external call, billing by line.
compelledtonelevel | IDU | 330 | Amplitude of compelled tones.
congestiontones | count | 3 | Tones in the fast busy cycle.
congestionofftime2 | ms | 600 | Duration of the interval between congestion tones.
alarmsonqualtime | ms | 500 | Qualification time for trunk alarms (time to wait after the commencement of a trunk alarm before the TCP is notified).
alarmsoffqualtime | ms | 400 | Qualification time for trunk alarm end (time to wait after a trunk alarm state ended before the TCP is notified).

Refer to MFS editable parameters for more information.