SL-100 Web Log

Tone Generation With EDRAM

January 27th, 2024-January 1st, 2025

The DMS-100 normally uses a handful of special tone generator cards to produce certain tones like receiver off hook tone (ROH) and 'milliWatt' (mW) test tones. I don't have any of those cards for my switch because they weren't in any of the frames I took from the university. However, through a special feature of the EDRAM, ROH and mW tones can be generated by the EDRAM.

There is a special file, loaded similar to announcement sets, which contain the tone samples used by EDRAM to generate those tones. That file is MWTTONE.

Unfortunately, MWTTONE was not present on my switch since the university wasn't using this feature. I did have a copy, but initially didn't have any good way to get files on and off the switch.

However, I remembered that the copy of MWTTONE I have is actually an S-record format file. That means it is ASCII clean and could be sent to the switch through a terminal and inputted into a text file.

I was able to use a text editor on the switch and the ascii file send capability of minicom, the terminal emulator I use, to get the file transferred onto the switch. This was a huge pain and had issues with missing lines that had to be corrected on a second pass using the text editor, but eventually I had the file correct.

The first time I tried to set up the EDRAM tone functionality, I had some issues that caused the switch to stop recognizing the EDRAM until I rebooted. I eventually tried again later and got it working the second time around.

Anyway, the first step is to make sure we've got a block of PROM in the DRAMS table:

DRAMCARD TMTYPE TMNO TMCKT  CARDCODE
                                                                    CARDINFO
----------------------------------------------------------------------------
    0  4    DTM    0     0    1X80BA
PROM (3) $

We point to the MWTTONE file in EDRAMINV to be loaded into this slot:

         EDRAMNM                 TUPINFO
----------------------------------------
       DTM  0  4            ANN  MWTTONE

Finally, we can add MWTTONE to PMLOADS:

                        LOADNAME
                         ACTFILE            ACTVOL
                         BKPFILE            BKPVOL    UPDACT
------------------------------------------------------------
                         MWTTONE
                         MWTTONE          F02LPMLD
                         MWTTONE          F17LPMLD         N

That takes care of the EDRAM pieces, then we need to configure the tones. We'll start with the T102 test lines, first up are the CLLIs to create:

            CLLI ADNUM TRKGRSIZ                         ADMININF
----------------------------------------------------------------
        TERM102L    77        0        TERMINATING_102_TEST_LINE
        TERM102T    79        5        TERMINATING_102_TEST_LINE

Then we create trunk groups in TRKGRP:

        GRPKEY
                                                                     GRPINFO
----------------------------------------------------------------------------
      TERM102T
                                            TTL2   0   TLD NCOT TMW   1X00AB
 
      TERM102L
                                            TTL2   0   TLD NCOT LMW   1X00AB

Trunk group type TTL2 is a terminating 102 test line. The options are as follows:

• TRAFSNO - Traffic separation number (0 since we're not using it).
• PADGRP - The loss pad group. TLD is what the EDRAM guide suggested, I think.
• NCCLS - Operational measurements class to be incremented if GNCT occurs on this trunk group.
• MWSPRVSN - Determines whether the supervision type is 100 balance or 102 local, steady, or toll.
• MWDBLEVL - Set to the card code for the mW tone which also has the effect (when used with EDRAM) of setting the dB level. If you were using the actual hardware card, you should of course match the card you have.

The entry in TRKSGRP was created automatically when we enter these in TRKGRP:

         SGRPKEY  CARDCODE
SGRPVAR
                                                                     SGRPVAR
----------------------------------------------------------------------------
      TERM102T 0    1X00AB
    STD
OG NP WK 0 0 NO NO N N N 20 UNEQ $

We just need to make an entry for a trunk member in TRKMEM then.

          CLLI        EXTRKNM SGRP                   MEMVAR
-----------------------------------------------------------
      TERM102T              0    0              DTM    0  8

That's all we need for the milliwatt tone. Now we just need to put things in service.

First, we post the EDRAM in MAPCI with 'MAPCI;MTC;PM;POST DTM 0'. Then set the EDRAM to manual busy with 'BSY'. We can then reload the EDRAM with the new MWTTONE file with 'LOADPM'. Finally, we can return the EDRAM to service with 'RTS'.

From here, we'll need to post the trunk with 'TRKS;TTP;POST G TERM102T'. Then we busy all the trunk members and then return them all to service.

The trunk is now back in service, so we can setup a route in OFRT and then point a DN at it.

 RTE                                                                 RTELIST
                                                                     OPTIONS
----------------------------------------------------------------------------
  11                                  (          S        D       TERM102L)$
                                                                           $

Then in SERVORD we can make a new DN with 'NEWDN'. We create a single DN, 2225631009, RTE type DN, pointing to OFRT 11, no special options.

Note that a mW tone on a short loop is quite loud when you test calling it.

The receiver off hook tone is set up differently. We start in CLLI first.

            CLLI ADNUM TRKGRSIZ                         ADMININF
----------------------------------------------------------------
             ROH    73       10                RECEIVER_OFF_HOOK

This time, we make the tone in STN:

          SK
           TMTYPE  TMNO  TMCKTNO   CARDCODE MAXCONN TRAFSNO
-----------------------------------------------------------
     ROH   0
              DTM     0        9     1X80BA      10       0
 
     ROH   1
              DTM     0       10     1X80BA      10       0

• SK - Special tone key identifies the special tone and a member number.
• TMTYPE, TMNO, TMCKTNO - Addresses the location of the card providing the tone.
• CARDCODE - Specifies the card providing the tone (1X80BA for the 17 minute EDRAM).
• MAXCONN - Specifies the maximum number of simultaneous connections to the trunk circuit. Some cards and tone types have a maximum number specified in the data schema manuals which should probably be followed.
• TRAFSNO - Specifies the traffic separation number (or 0 if we're not using it).

We shouldn't need to reload the EDRAM again since we already did it. Possibly static data needs to be reloaded or something, but I'm not sure.

We can post the new trunk with 'MAPCI;MTC;TRKS;TTP;POST G ROH'. Then we can busy all the trunk members and then return all of them to service.

As before, we can route a DN to it if we want using the 'NEWDN' command in SERVORD.