Mike's PBX Cookbook

Buffer Overflow Errors

ERR0030 and ERR0180 messages indicate Buffer Overflow problems. While these types of errors may not be critical, they can cause Meridian processing to slow down dramatically when numerous errors are generated. If errors are too numerous, they can cause an entire IPE shelf or Superloop to go out-of-service. Buffer Overflow Messages can be generated by defective PBX equipment such as Line, Station, Net and/or Controller Cards.

Buffer Overflow Messages are described below:

ERR0030 x x tn rt clock:
NE-500 output buffer overflow. NE-500 set buffer may not be large enough or is not being emptied.

ERR0030 messages may be related to:

  1. Defective Line Card(s)
  2. Defective Controller Card on an IPE shelf; (There is one Controller Card per shelf)
  3. Defective NET Card controlling a superloop. (A superloop can control two shelves, 0&1. Each shelf has its own Controller that is assigned a unique Controller number).
ERR0180 x x rt clock:
Trunk output buffer overflow. Trunk output buffer may not be large enough.

ERR0180 messages may be related to:

  1. Defective Trunk Cards
  2. Defective Controller Card on an IPE shelf; (There is one Controller Card per shelf)
  3. Defective NET Card controlling a superloop. (One superloop can control up to two shelves (0&1). Each shelf has it's own Controller that is assigned a unique Controller number).

Action:

Determine the relevant TN's

To process repairs, record the values in the third field of the ERR record. These values are
Hex-TN numbers that can be converted into identifiable TN locations via the CONVERT command in LD 32.

The following are examples of Buffer Overflow Error Messages: 

ERR0030 320000 00001508

ERR0030 320000 00001608

Use the CONVERT command in LD32 to convert the Hex-TN field to a recognizable TN.

LD 32
. CONV 1508 (Note: Leading zeroes in front of 001508 should be stripped)
->  020 0 02 04 (Loop, Shelf, Slot, Circuit)

. CONV 1608 (Note: Leading zeroes in front of 001608 should be stripped)
->  020 1 02 00 (Loop, Shelf, Slot, Circuit)

Reset relavent Equipment

Convert several of the TN-Hex values to see if they point to a specific card/shelf.
If they do:

  1. Disable the line card at the problem TN via LD 32;
  2. Reseat the line card;
  3. Enable the line card via LD 32.

LD 32
.DISC 020 0 02 (Disable Card)
.ENLC 020 0 02 (Enable Card)
.STAT 020 0 02 (Show State of card)

5. If the buffer errors don't stop, replace the line card. (Be sure to disable the line card via LD 32 before replacing it.)

6. If Buffer Errors point to several TNs, check to see if the TN’s are on the same loop.

  1. If errors occur on the same loop, the NET card controlling that loop could be defective.
  2. If errors occur on one shelf only:
    1)    The Controller Card for that shelf could be defective
    Or
    2) The NET card controlling that loop/shelf could be defective

7. Reseat and/or replace NET Cards (NT8D04) in the following manner:

A) Disable the affected Loop via LD 32 using the DISL command. 

LD 32
.DISL 20

(In the example above, loop-20 is disabled)

B) Disable the Controller Card (NT8D01) on each shelf via LD 32 using the DSXP command.
Note: Each shelf has one Controller card. Controller Numbers can be determined by
observing the number flashing on the front of the Controller Card display. Normally, the
Controller Card flashes: CO xx where xx is the Controller-Number.

LD 32>
.DSXP 4

(In the example above, Controller 4 is disabled)

8. Manually disable the NET card (NT8D04 in slots 0-7) by moving the card’s toggle switch from ENL to DIS..

9. Reseat the NET card and cables.

10. Manually re-enable the NET cards by moving the card’s toggle switch from DIS to ENL.

11. Enable the affected loop via the LD 32 ENLL command.

LD 32
.ENLL 20

12. Enable the Controller via the Loop 32 ENLX command.

LD 32
.ENLX 4

13. Buffer Overflow Errors should now stop. If Errors don’t stop, replace the NET card (using the procedures previously outlined) and re-check its cables.

14. A continuation of Errors means that problems could exist in anything from the NET Card to its Cabling to the Controller Card. Replace and attempt to isolate/test each component separately. Ensure NET cables are securely fastened.