SL-100 Web Log

Configuring Basic Treatments

December 3rd, 2023

After configuring some very basic translations in the last post, there were still some important improvements to make.

While I could place calls in my switch, if I dialed anything other than a working number the line would simply reset back to dialtone.

This is because we don't have any treatments configured. The exact sequence is that when the switch encounters a problem completing a call, it handles it with a treatment specific to that line or trunk type. If it can't find a definition specifc to that line or trunk type, it'll look for a generic office treatment definition for that treatment. If it still can't find that, it'll look for the generic office treatment definition for reorder. If it still can't find that, the line will simply return to an idle condition, detect that it's still off hook in the case of a line, and present new dialtone.

Treatments vary, but generally they're an announcement, a tone, or some combination of the two. We'll start with some simple tones since I don't have an announcement card configured yet.

We have some dependencies to walk again. Treatments are defined in the TREAT subtables of TMTCNTL. They can use couple different route selectors to direct to the treatment, one that goes directly to a CLLI and another that uses the various office routing tables. Office routes are defined in OFRT and CLLIs are defined in CLLI. Once the CLLI is defined, the actual tone, in this case, is defined in TONES.

We'll start with the RODR treatment, which is reorder tone. We need to first add a CLLI for the T120 tone, which forms the basis of reorder tone, in table CLLI.

            CLLI ADNUM TRKGRSIZ                         ADMININF
----------------------------------------------------------------
            T120    84       10                         FASTBUSY

• CLLI - the CLLI code to be defined. It's important to note there are a number of special reserved-purpose CLLIs that shouldn't be allocated for user defined ones. There's also some common conventions, like T120 referring to north-american 120 interruptions per minute low tone.
• ADNUM - an administrative number unique to each CLLI. It's important to note that some of the administrative numbers are specially reserved for certain special CLLIs. Those are in the range of 1 to 50. 0 should not be used because certain external systems do not accept it as valid.
• TRKGRSIZ - Specifies the number of members in a trunk group. I think this doesn't apply to all CLLIs since they're not all defined in terms of traditional trunk groups with members.
ADMININF - A free form text area available for operating company use for administrative information.

The T120 tone definition goes in TONES.

          CLLI TRAFSNO  SEGTIME  OFFTIME          TONEPATT
                       TONETYP
                                OFFTONE
                                 MAXDURN  MAXCONN
                                      FNTONID
                        TONESGRP
----------------------------------------------------------
          T120       0       25       25            101010
                            LO
                            SILENT_TONE
                                      30      255
                                    TONE_NULL
                               N

• CLLI - We use the same CLLI we already defined in the CLLI table.
• TRAFSNO - Traffic separation number for tracking usage. Set to 0 if we don't use this.
• SEGTIME - Time that the tone is 'on' in 10ms increments.
• OFFTIME - Time that the tone is 'off' in 10ms increments.
• TONEPATT - Pattern of tone 'on' (1) and 'off' (0) with each digit representing SEGTIME and OFFTIME for 1 and 0 respectively.
• TONETYP - Tone used during the on time. Several tone types are available depending on the nationality of the switch.
• OFFTONE - Same thing as TONETYP, but for during the off time.
• MAXDURN - Maximum duration of the tone in seconds before the call is disconnected from the tone.
• MAXCONN - Maximum connections. However, this does nothing for tones defined in TONES because they are effectively unlimited, being generated in the line peripherals themselvs.
• FNTONID - Used for packet networks to identify the tone to be used. Not relevant for TDM switching.
• TONESGRP - Indicates whether there are additional tone definitions in table TONESGRP. The data manual I was looking in didn't cover TONESGRP, however, so I'm not sure what this practically means.

Here, we've defined tone T120 where the on and off time are 250ms each. The cadence is a simple repeated on/off cadence. The whole cycle is 500ms long before it repeats, thus the tone repeats 120 times per minute. When the tone is on, it is 'LO' tone, and silent when off. This is the typical north-american 'reorder' tone.

Our treatments get added in TMTCNTL. Each tuple in TMTCNTL represents a different group of treatments that apply in different scenarios. OFFTREAT is the generic default set, used when the other sets don't define a treatment. The TREAT subtable is where the actual treatments get defined.

EXTTMTNM   TREAT
----------------
OFFTREAT (    0)
     LNT (    0)
ITTRKGRP (    0)
TITRKGRP (    0)
INTRKGRP (    0)
PXTRKGRP (    0)
     DTH (    0)

The treatment group names are briefly outlined as follows:

• OFFTREAT - Generic treatments for incoming trunks. Every treatment applicable to trunks should be defined.
• ITTRKGRP - Treatments specific to intertoll trunks that override those in OFFTREAT.
• INTRKGRP - Treatments specific to CAMA/AMR5 trunks that override those in OFFTREAT.
• LNT - Treatments specific to lines. Every treatment applicable to lines should be defined, but OFFTREAT will be used if they are not.
• TITRKGRP - Treatments specific to local trunks that override those in OFFTREAT.
• PXTRKGRP - Treatments specific to PBX trunk groups that override those in OFFTREAT.
• TOPS - Treatments specific to TOPS trunk groups that override those in OFFTREAT.
• INT101TT - Treatments specific to international 101 test trunk groups that override those in OFFTREAT.
• PRIVLNTT - Treatments specific to DMS-300 private line trunk groups that override those in OFFTREAT.

I created the RODR treatment in the TREAT subtable of OFFTREAT.

TREATMT LOG           FSTRTE
----------------------------
   RODR   N S           T120

• TREATMT - The identifier of the treatment being defined.
• LOG - Enable logging each time translation is routed to this treatment.
• FSTRTE - First Route. Consists of a selector (S or T) where S routes directly to a CLLI and T routes to a route list in one of the office route tables.

Now if we dial something invalid, we get the T120 tone instead of just resetting to dialtone. We do eventually reset to dialtone after the T120 tone finishes, so we can fix that by using LKOUT in the line-specific treatment table, LNT.

We should not use IDLE, LKOUT (lockout), or ROH (receiver off hook tone) on any trunks, so we'll only make this change in the LNT TREAT subtable. Before we do that, though, we'll have to implement this as a route list of T120 followed by LKOUT.

We can build that in OFRT:

 RTE                                                                 RTELIST
                                                                     OPTIONS
----------------------------------------------------------------------------
   1 (S D T120) (S D LKOUT) $
                                                                           $

• RTE - Specified a route index number for this route list.
• RTELIST - Describes the actual members of the route list. There are many different selectors that allow different behaviors.
• OPTIONS - Various options related to the route selectors in use.

This route is set to first play T120 tone, and after it finishes, lockout the line (which prevents it from returning to dialtone until it is hungup and taken off hook again). We can reference it in the TREAT subtable of LNT:

TREATMT LOG           FSTRTE
----------------------------
   RODR   N  T     OFRT    1

This time, rather than refer to the CLLI directly, we reference the routelist we created.

It's worth noting, though, that we won't hit this treatment most of the time because mostly our treatments are undefined and are going to end up in OFFTREAT right now.

There are a lot of other possible treatments and in general, it's good practice to configure all treatments in at least OFFTREAT and (on end office switches) LNT to prevent unusual conditions. If announcements are used, it's a good idea to use a routelist to play the announcement and then a tone so that if the announcement isn't working, the tone takes it's place. Lastly, for LNT treatments, it's a good idea to use LKOUT as the last entry in each routelist to prevent unwanted resets to dialtone as opposed to IDLE, which will reset to dialtone, or unterminated lists which will route to GNCT.

The data manual also points out that GNCT should be defined so that it ends up at a nonblocking tone to prevent infinite loops when the end of route lists are hit.

We'll define a BUSY treatment here as another example, but it will be more of the same, so here it is quickly, starting in CLLI:

            CLLI ADNUM TRKGRSIZ                         ADMININF
----------------------------------------------------------------
             T60    85       10                         SLOWBUSY

Then we define the actual tone in TONES:

          CLLI TRAFSNO  SEGTIME  OFFTIME          TONEPATT
                       TONETYP
                                OFFTONE
                                 MAXDURN  MAXCONN
                                      FNTONID
                        TONESGRP
----------------------------------------------------------
           T60       0       50       50            101010
                            LO
                            SILENT_TONE
                                      30      255
                                    TONE_NULL
                               N

We pull in the new T60 tone in the OFFTREAT TREAT subtable:

TREATMT LOG           FSTRTE
----------------------------
   BUSY   N S            T60

Again, we make a routelist that ends in LKOUT for the LNT TREAT subtable:

 RTE                                                                 RTELIST
                                                                     OPTIONS
----------------------------------------------------------------------------
   2 (S D T60) (S D LKOUT) $
                                                                           $

And add this routelist into the LNT TREAT subtable:

TREATMT LOG           FSTRTE
----------------------------
   BUSY   N  T     OFRT    2

At some point, I'll properly go through the list of possible treatments and assign them all properly, but this was not that time. I just wanted to fill in the bare minimums.