Re: [asterisk-users] what is the effect of high LBO settings?
On Mon, Mar 2, 2009 at 3:07 PM, Brandon B. bran...@brellsystems.com wrote: On Fri, Feb 27, 2009 at 7:49 PM, Jared Smith jsm...@digium.com wrote: As I understand it, the LBO is effectively an attenuation value, with a higher number meaning less attenuation. This way, you don't get too hot of a signal with a short cable, or two low of a signal on long cable. Just how far is your Asterisk box from the demarcation point? This system is connected to a CSU in the same room that provides the physical T1 line. I've always set the LBO setting at 0 for this because I've never had a long line to deal with. Since 0 works for me, I'm going to assume it's the correct setting with the demarc point (i.e. the Paradyne CSU) in the same room -- right? It's slightly confusing with settings 5,6,7 labelled CSU and no description as to when to use those levels. Could you provide any suggestion for when levels 5,6,7 would be appropriate? From what you say an LBO setting of 5 would boost the signal level, which could be hot. Is there any chance this would cause the card to fail after a while? It appears this site just had 4 port Digium card fail today. Turns out this problem was not the card, but another hardware issue. The hard disk with Reiserfs eventually cratered and took the system down, and the entire filesystem appears to be unrecoverable. I've changed the LBO settings from 5 to 0, and the system is working fine. If anyone has anything to add regarding the effect of different LBO settings I think it might be helpful to have this documented. Brandon B. ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] what is the effect of high LBO settings?
On Fri, Feb 27, 2009 at 7:49 PM, Jared Smith jsm...@digium.com wrote: On Fri, 2009-02-27 at 14:07 -0700, Brandon B. wrote: As of yet, I am unwilling to change the LBO to 0 to where it probably should be because the system is working and I'm not sure exactly what the LBO does. I'm aware some changes were made to deal with low audio levels. LBO stands for Line Built Out... it's essentially a measurement of the distance between your demarcation point (d-marc/smart jack/NIU) and your Asterisk box. As you can see from a sample system.conf (from DAHDI) or zaptel.conf (from Zaptel), it's an integer value from the following table: 0: 0 db (CSU) / 0-133 feet (DSX-1) 1: 133-266 feet (DSX-1) 2: 266-399 feet (DSX-1) 3: 399-533 feet (DSX-1) 4: 533-655 feet (DSX-1) 5: -7.5db (CSU) 6: -15db (CSU) 7: -22.5db (CSU) As I understand it, the LBO is effectively an attenuation value, with a higher number meaning less attenuation. This way, you don't get too hot of a signal with a short cable, or two low of a signal on long cable. Just how far is your Asterisk box from the demarcation point? This system is connected to a CSU in the same room that provides the physical T1 line. I've always set the LBO setting at 0 for this because I've never had a long line to deal with. Since 0 works for me, I'm going to assume it's the correct setting with the demarc point (i.e. the Paradyne CSU) in the same room -- right? It's slightly confusing with settings 5,6,7 labelled CSU and no description as to when to use those levels. Could you provide any suggestion for when levels 5,6,7 would be appropriate? From what you say an LBO setting of 5 would boost the signal level, which could be hot. Is there any chance this would cause the card to fail after a while? It appears this site just had 4 port Digium card fail today. Also, I am trying to cross connect with another Asterisk system with the normal LBO setting (i.e. span=1,1,0,esf,b8zs) but as of yet the systems aren't seeing each other at all. Could the side with the high LBO be confusing the other side somehow? Shouldn't be... you did use a T1-crossover cable to cross-connect the two Asterisk boxes, right? I've got a little T1 cross-connect diagram at http://www.asteriskdocs.org/cables/ if you need a reference. Yes, it's a T1 cross over and this problem was resolved after plugging into a working Digium card on the other end. Brandon B. ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
[asterisk-users] what is the effect of high LBO settings?
I'm working on an Asterisk system with all of it's PRI ports configured with the LBO setting at 5, like this: span=3,0,5,esf,b8zs As of yet, I am unwilling to change the LBO to 0 to where it probably should be because the system is working and I'm not sure exactly what the LBO does. I'm aware some changes were made to deal with low audio levels. Does anybody know what audio effects could this possibly have with short cabling? Also, I am trying to cross connect with another Asterisk system with the normal LBO setting (i.e. span=1,1,0,esf,b8zs) but as of yet the systems aren't seeing each other at all. Could the side with the high LBO be confusing the other side somehow? Brandon. ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
Re: [asterisk-users] what is the effect of high LBO settings?
On Fri, 2009-02-27 at 14:07 -0700, Brandon B. wrote: As of yet, I am unwilling to change the LBO to 0 to where it probably should be because the system is working and I'm not sure exactly what the LBO does. I'm aware some changes were made to deal with low audio levels. LBO stands for Line Built Out... it's essentially a measurement of the distance between your demarcation point (d-marc/smart jack/NIU) and your Asterisk box. As you can see from a sample system.conf (from DAHDI) or zaptel.conf (from Zaptel), it's an integer value from the following table: 0: 0 db (CSU) / 0-133 feet (DSX-1) 1: 133-266 feet (DSX-1) 2: 266-399 feet (DSX-1) 3: 399-533 feet (DSX-1) 4: 533-655 feet (DSX-1) 5: -7.5db (CSU) 6: -15db (CSU) 7: -22.5db (CSU) As I understand it, the LBO is effectively an attenuation value, with a higher number meaning less attenuation. This way, you don't get too hot of a signal with a short cable, or two low of a signal on long cable. Just how far is your Asterisk box from the demarcation point? Also, I am trying to cross connect with another Asterisk system with the normal LBO setting (i.e. span=1,1,0,esf,b8zs) but as of yet the systems aren't seeing each other at all. Could the side with the high LBO be confusing the other side somehow? Shouldn't be... you did use a T1-crossover cable to cross-connect the two Asterisk boxes, right? I've got a little T1 cross-connect diagram at http://www.asteriskdocs.org/cables/ if you need a reference. -- Jared Smith Digium, Inc. | Training Manager ___ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
