Dialogic Support Helpweb
Dialogic® DM3 & JCT Media Boards
Configuring T1 Framing and Coding - JCT-series
Description:If coding on Dialogic® T1's is not configured to match the PBX, Dialogic® Service could fail to start. By default, when selecting "None" (robbed-bit), coding is set to AMI and framing is set to D4. This tech note will explain how to change coding and framing when using Springware T1 cards, and how to avoid start up problems.
Symptom:
When selecting "None" (robbed-bit) in the Dialogic® Configuration Manager (DCM) (under the “Interface” Tab), default settings for coding and framing are set to AMI and D4 respectively. If a T1 from a PBX or Central Office is connected to the Dialogic® cards before either side is configured, it could cause the Dialogic system service to fail start-up if there is a coding mismatch (e.g. If Dialogic system service is set to AMI coding and PBX is set to B8ZS coding, there is a mismatch) The problem is more noticeable if there are errors or noise on the line. If only a few channels have errors or noise, Dialogic Service may fail at startdrv.exe. If all channels have errors and noise, Dialogic Service may fail at genload.exe (one or more boards may fail to download).
Reason for the problem:
DDialogic Service fails to start because the control processor gets flooded with interrupts from the PMC framer chip due to incorrect configuration. If a user plugs in a T1 (that is configured for B8ZS and that has noise or excessive errors) from a PBX or Central Office, into a Dialogic® Springware T1 board (e.g. Dialogic® D/480JCT) that is configured for defaults, (AMI, D4...NONE for ISDN), it is possible that Dialogic Service will not start. It has been noticed that the more channels that have errors and noise, the quicker Dialogic Service will fail to start. If the entire T1 is in this state, it is possible that boards will fail to download (genload.exe fails), and Dialogic system service service will not start. If there are fewer channels in this state, Dialogic system service may pass genload (firmware actually downloads to the installed boards) but may fail to start devices (startdrv.exe fails). Dialogic system service will then fail to start.
Fix / Solution:
The problem is addressed by a .prm file change / selection. In particular, the following steps can be taken to address the problem:
- Make sure that the coding on the T1 from the PBX or C.O. is configured to match the Dialogic Springware board defaults (AMI, D4) before connecting it to a Dialogic® board. This configuration should be done by the actual PBX administrator / Central Office.
- 2. Make sure that framing and coding are properly configured to match the PBX. If the coding and framing of the PBX / C.O. are already configured or cannot be changed, then coding and framing can be changed on the Dialogic system service.. By default, Dialogic system service is set to AMI (No zero code suppression 00), D4 (00). You can change it to B8ZS by doing the following:
Coding:
;--- ZERO CODE SUPPRESSION MODE (Parameter type 20H) ;--- Sets the Zero Code Suppression mode for T1 ;--- Possible values for the data are as follows: ;--- 00H = No zero code suppression. ;--- 01H = B8ZS. ;--- 02H = Bit 7 jamming. ;--- The default data value is 00H (no zero code suppression) 0020 01
OR:
- Modifying the Zero Code Suppression Mode parameter (0020) in the spandti.prm file (Dialogic\data).
;--- ZERO CODE SUPPRESSION MODE (Parameter type 20H)
;--- Sets the Zero Code Suppression mode for T1
;--- Possible values for the data are as follows:
;--- 00H = No zero code suppression.
;--- 01H = B8ZS.
;--- 02H = Bit 7 jamming.
;--- The default data value is 00H (no zero code suppression)
0020 01
NOTE: NOTE: In order for this to take effect, the spandti.prm file has to be read into DCM. This can be done by clicking on the “Misc” tab, Clicking on “ParameterFile”, and entering “spandti.prm” in the “Value” drop down box.
- 3. Framing for Dialogic T1 by default is set to D4 (00). In order to change framing to ESF for Dialogic Springware T1, the following must be done:
Framing:
a. Modify the Protocol Type parameter in the spandti.prm file. In order for this to take effect, the spandti.prm file has to be read into DCM. This can be done by clicking on the “Misc” tab, Clicking on “ParameterFile”, and entering “spandti.prm” in the “Value” drop down box.
