[nsp] E1 (G703-X21-V35) interfaces

[Stephen J. Wilcox]

Hi Vandy,

> In Australia, you have a choice to receive BNC or RJ45 from your
> provider.

ok this is just terminology, my previous response was correct.. bnc and rj45 are
the connectors that go on the wire which would be coaxial or cat5

> My voice provider asked if I wanted "75 Ohm BNC, 120 Ohm RJ45?"

right, and you want rj45 to plug into the vwic. but its the same thing 
transmitted on both, you just need a convertor - either a balun or cable.

> G703 is used to get an unstructured (unframed) E1 which will bump the
> throughput to 2048Kbits/s (using all 32 64K TDM Channels).

g703 means 2048Kbps, but no channels. g704 is framing that goes on top of the
g703.. it provides a timing mark that fills up 64k of the 2048k leaving you
1984k which you can allocate up. for voice that means 31x64k channels. if you
run ISDN on that then one channel (15) is used for signalling leaving 30
channels for your voice. note that non-isdn voice circuits tend to keep the
channel 15 empty so still use 30 channels

> X21 and V35 connections are available IF you want the provider to
> provide the DSU and hand off to the CPE (you) a serial connection (x21
> or v35).
> 
> This is used for fractional E1's because the provider can timeslice the
> TDM and hand you 1024Kb, so I was told.

right.. but in which case its a whole 1024k you get (not chopped up into 16x64k) 
and you cant run TDM voice over it. i was under the impression you are asking 
for a voice circuit (isdn?) not a data circuit?

if you want a data circuit then just purchase an x21 card (wic-1t) but this 
doesnt support voice, channelisation or add-drop etc

> Cisco does sell a BNC to RJ45 converter.  Forget that.  I just need to
> have the RJ45/48 handoff specified in the order.

Yup.. 

Steve

> 
> 	-=Vandy=-
> 
> 
> -----Original Message-----
> From: Stephen J. Wilcox [mailto:steve at telecomplete.co.uk] 
> Sent: Wednesday, June 23, 2004 1:32 PM
> To: Vandy Hamidi
> Cc: cisco-nsp at puck.nether.netSubject: Re: [nsp] E1 (G703-X21-V35)
> interfaces
> 
> Hi Vandy,
>  answers below..
> 
> On Tue, 22 Jun 2004, Vandy Hamidi wrote:
> 
> > Building out a new office in Australia and I'm specing out a router to
> > plug in a VOICE E1.
> > 
> > The voice provider stated, "We can terminate it on whatever interface
> is
> > suitable to your equipment on site - G703 unstructured or X.21 or V.35
> > structured services"
> > 
> > >From what I understand.  G703 is direct E1 from the Provider.  X21
> and
> > V.35 are hand-offs after it has been run through the providers DSU.
> > 
> > My questions are:
> > 1. What is unstructured v. structured
> 
> Probably g703 unframed vs g703 with g704 framing which is channelised
> altho if
> this is for voice it surely has to be channelised? which would also
> confuse me
> about them offering x21 and v35 which wouldnt permit framing either. 
> 
> I think you need to confirm with them that they are talking to you about
> an ISDN
> circuit and not a point-to-point E1 circuit, it sounds like theyre
> confused..
> either they are selling you the wrong thing or the person you're
> speaking to is
> confusing all the options is sales-droid-instruction-manual is giving
> him
> 
> > 2. I've seen unbalanced and balanced for g703.  What the heck is that?
> 
> usually it means coaxial vs cat5 physical presentation, you can convert
> with a 
> balun (balanced to unbalanced).. it just affects the electrics of the
> physical 
> layer
> 
> > 3. Do I need to get a special type of VWIC for this? (going into a
> Cisco
> > 2651XM)
> 
> assuming this is a channelised e1 doing isdn yes you need ot make sure
> you get a 
> vwic, wic-1t wont do framing or voice
> 
> > 4. What type of connector is going to be handed off.
> > 	Cisco VWIC is RJ45/48 and I've heard G703 is BNC?????
> 
> the vwics are rj45 .. just get a convertor, cisco sell an rj45-coax/bnc
> cable or 
> you can try to make one but its a bit fiddly
> 
> HTH
> 
> Steve
> 
> > Any information to clarify this fog would be greatly appreciated.
> > Thanks,
> > 
> > 	-=Vandy=-
> > 
> > 
> > 
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> 
> 
> 
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