[asterisk-users] t1 cards

Fri Oct 3 10:30:50 CDT 2008

T1 is NOT DSL.  Most T1 links you purchase now are brought into your 
building with a type of DSL conversion to extend the distance between 
repeaters/amplifiers.  T1 is purely a digital signal.  DSL converts the 
ones and zeros to audio(multiple tones to provide multi channels of 
data).  A simple analogy is comparing a T1 to DSL as a serial port to a 
modem.

Back in the old days before fiber, copper T1's between CO's had their 
repeaters placed aproximately 1 mile apart.  Best case going T1 port to 
T1 port, I would not expect this to work reliably at distances greater 
than one mile or 1.6 km but that does depend on the quality of the cable 
also.

But in my mind, I would be seriously concerned about lightening 
protection.  I have been around telco's and privately owned facilities 
for a long time and see lightening to be a very serious issue in this 
scenerio. I have seen short distance copper replaced by fiber because of 
issues over time with lightening damage despite having proper telco 
grade protection.

Lyle

Jeff LaCoursiere wrote:
> I would say miles.  DSL limits for equiv bandwidth is around 3 miles if I
> recall correctly.
>
> j
>
> On Fri, 3 Oct 2008, Eric Fort wrote:
>
>   
>> without any other hardware than 2 bare ass pci based t1/e1 cards wired back
>> to back how far can one go between them?  additional hardware defeats the
>> purpose.
>>
>> Eric
>>
>> On Fri, Oct 3, 2008 at 3:01 AM, Gordon Henderson
>> <gordon+asterisk at drogon.net<gordon%2Basterisk at drogon.net>
>>     
>>> wrote:
>>>       
>>> On Fri, 3 Oct 2008, Eric Fort wrote:
>>>
>>>  yes, more than 300 meters (longer than copper based ethernet allows).  Yes
>>>       
>>>> to E1, as I understand it, it's just a config change on many cards anyway.
>>>> I'm specificly looking at pci based t1/e1 cards because I'm finding single
>>>> port cards on ebay going for 100-200 usd.  in some cases I may want to
>>>> drive
>>>> a channel bank at the far end, thus t1/e1.  anyone have experience on how
>>>> far these pci based cards will drive when wired back to back?
>>>>
>>>>         
>>> Looks like this is the thing then:
>>>
>>>  http://www.blackbox.com/Catalog/Detail.aspx?cid=381,1452,1468&mid=5362
>>>
>>> Just over $1000 a pair...
>>>
>>> couple that with an OpenVox PRI card at one end, channel bank at the other,
>>> and off you go...
>>>
>>> Gordon
>>>
>>>
>>>
>>>       
>>>> Eric
>>>>
>>>> On Thu, Oct 2, 2008 at 11:34 PM, Gordon Henderson <
>>>> gordon+asterisk at drogon.net <gordon%2Basterisk at drogon.net> <
>>>> gordon%2Basterisk at drogon.net <gordon%252Basterisk at drogon.net>>> wrote:
>>>>
>>>>  On Thu, 2 Oct 2008, Eric Fort wrote:
>>>>         
>>>>>  I presently need to connect a few channels of voice and data between
>>>>>
>>>>>           
>>>>>> multiple locations where I own the copper between them.  Each location
>>>>>> exceeds 300M from any other location.  I'm thinking of generating T1's
>>>>>> and
>>>>>> running those between locations.  If I use PC based cards wired back to
>>>>>> back
>>>>>> (I can do that, right?) what kind of distance can I expect to be able to
>>>>>> span without needing repeaters?  What inexpensive cards can you
>>>>>> recommend
>>>>>> for use with asterisk?  I'm considering either digium or sangoma.  Would
>>>>>> I
>>>>>> get any better performance if I used a sync-serial card connected to a
>>>>>> separate csu/dsu?
>>>>>>
>>>>>>
>>>>>>             
>>>>> 300 metres, right? (not 300 miles?)
>>>>>
>>>>> Why stop at T1? Go for E1 :) with the right kit at each end you ought to
>>>>> be
>>>>> able to get 2Mb/sec or more. (distance depending)
>>>>>
>>>>> Personally, I'd go for a technology that gave me Ethernet at each end -
>>>>> then it makes it much easier to mix voice and data - But using something
>>>>> like a sync. modem and line driver then you need a media converter of
>>>>> some
>>>>> sorts at each end which might bump up the cost - at the savings of the E1
>>>>> card in the PC though. Last time I had bare copper to play with (a BT
>>>>> EPS8
>>>>> circuit) I had a 2Mb modem at each end going into a Cisco 2600 which was
>>>>> running CHDLC over the link and acting as nothing more than a dumb media
>>>>> converter to give me Ethernet at each end. This was 6 years ago though.
>>>>>
>>>>> Ah, Looks like the technology has improved somewhat:
>>>>>
>>>>>  http://www.blackbox.com/Catalog/Detail.aspx?cid=381,1452,1468&mid=5261
>>>>>
>>>>> From the UK site:
>>>>>
>>>>> Or even:
>>>>>
>>>>>  http://www.blackbox.com/Catalog/Detail.aspx?cid=425,1423,1424&mid=4946
>>>>>
>>>>> (same thing from the UK site:)
>>>>>
>>>>>
>>>>>
>>>>> http://www.blackbox.co.uk/solutions/display.asp?cs=dvh&id=1&doc=lb300a-r2&tx=LAN&sx=Network%20Appliances
>>>>>
>>>>> You need a pair, obviously...
>>>>>
>>>>> Hm. US site is $305, UK ?253. Rip-off Britain again by the looks of
>>>>> it....
>>>>>
>>>>> As for inexpensive cards - OpenVox. Their E1 cards seem to work OK, but
>>>>> if
>>>>> using a LAN extender, then they're not neeed at all...
>>>>>
>>>>> Gordon
>>>>>
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>
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