NEC 2000IVS. Two of our buildings are connected with 8 channels of a T1. Most of the time it works great, but occasionally when you try to call from site 1 to site 2 it rings once and then you get a busy signal. Also on transfers to building 2 they ring back to the transferring station. It seems to clear up after an hour or so. This has been going on for over 2 years, but when we have called our vendor they can never find any problems. Any thoughts would be gratefully appreciated
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Intermittent connection problem
- Thread starter femoric
- Start date
- Thread starter
- #3
not sure about channel banks, but I looked at the cards in the system at the main site and it has two 24DTA-A cards in it. I think these would be the cards that connect the two buildings.
If you need anything else let me know. Im not an expert but I have some system manuals and I am willing to learn.
If you need anything else let me know. Im not an expert but I have some system manuals and I am willing to learn.
belevedere
Instructor
Look for a SC-00 card. If you have one in each site, then you have the CCIS connection feature. This relys on a solid clock and T-1 connection to stay active. In either case I would check out the clocking between sites. Look for a solid green LED midway down on the CPU card. This indicates a received clock signal from an outside source. Turn on the alarms for T-1 and CCIS DCH. CMD EA2>20,21,22,30,31,32, and set them to a "0" to track alarms. This may help.
MercuryComm
Vendor
This sounds like a clocking problem. If you have a CSU/DSU breaking out channels for voice and data make sure you have it programmed at the main site to clock off of the switch and at the remote end to clock off of the span coming to it. You also might want to check and make sure your dip switch settings on your 24DTA cards are set correctly. If you have a T-1 coming in from Telco make sure you have that card set as the main clock source, and the other one as the secondary clock source. Hope this helps...
OzzieGeorge
Programmer
Another possibility is that the clock speed is incorrectly set. There is a higher clock speed option for ETSI cards you would need to check the dip switch settings for your cards.
- Thread starter
- #7
Belevedere, There is a SC00 card in the remote site And I beleive MercuryComm is correct that we have a CSU/DSU on each end that breaks out the channels. I can see that all of this is going to be way above my head, but I think your comments will be very helpfull when we get our vendor on site. If you guys can think of any other tips that might help that would be great. Thank you all for your time.
You need verify the clock source for the CCIS span.
There is a good chance that there is a clock source on the point to point span. This can be easily proved by changing some switch settings and having the cards in PIM 0. If you get a good NEC vendor they will know how to do this to confirm there is no clock on the point ot point.
If there is you will have to fight the telco to remove it or use it as the clock reference. Once again your vendor SHOULD know this. This is a very basic and simple support call. If they do not understand this call another vendor.
If you are doing drop and insert the CSU/DSU will have timing assignments that MUST be set correctly as well so that the master clock source is referenced form the PBX or other determinded master.
If not you will notice call setup issues but not dropped calls. This is common of a frame alignment issue all pointing back to timing on the circuit.
There is a good chance that there is a clock source on the point to point span. This can be easily proved by changing some switch settings and having the cards in PIM 0. If you get a good NEC vendor they will know how to do this to confirm there is no clock on the point ot point.
If there is you will have to fight the telco to remove it or use it as the clock reference. Once again your vendor SHOULD know this. This is a very basic and simple support call. If they do not understand this call another vendor.
If you are doing drop and insert the CSU/DSU will have timing assignments that MUST be set correctly as well so that the master clock source is referenced form the PBX or other determinded master.
If not you will notice call setup issues but not dropped calls. This is common of a frame alignment issue all pointing back to timing on the circuit.
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