G.703 interface query

[wmmak]

Hi all,

I confuse with WAN interface. Some SP say providing X.21, V.35, G.703 etc.

G.703 really makes me confused.

May I know that

1. is G.703 a physical layer standard?

2. is it talking about unframed E1 only, so it is not related to T1 standard, right?

3. if the SP provides G.703 interface for WAN connection, is it a MUST to install VWIC-1MFT-G703 for DATA only connection, any other choice??? Also, I should buy the cable CAB-E1-RJ45BNC???

Many Many Thanks in advance

Regards,

mak

[albert.remo]

Hi!

1. The most basic definition of G.703 is that it is a CCITT standard for transmitting voice over digital carriers such as T1 and E1. G.703 provides the specifications for pulse code modulation (PCM) at data rates from 64 Kbps to 2.048 Mbps. G.703 service is typically used for interconnecting data communications equipment such as bridges, routers, and multiplexers. G.703 is transported over balanced (120 ohm twisted pair) or unbalanced (dual 75 ohm coax) cable. Whether the G.703 is balanced or unbalanced depends on your geographic location and the carrier that supplies the service.

2. Yes, G.703 is for unframed service access but as the definition implies, it also is a standard for T1.

3. The module that you specified is only one of the many service modules that supports G.703. VWIC means its for voice application. Need not to buy the cable if you are to use balanced (120ohms) connections because you only need to use an RJ45 connected to a UTP using pins 1245.

Just ask your SP if the link they are providing also supports G.704. It is the standard for framed service access.

Check out this link!

http://ckp.made-it.com/g703.html

Regards,

Albert

[wmmak]

Hi Albert,

Then is there any T1 module with G.703 interface? or all T1 modules can be G.703 by extra items like CSU/DSU etc.? Like Router(T1 interface)(non-G.703)---> CSU/DSU(G.703)---> Circuit?

Or by means of suitable cable?

Regards,

mak

[albert.remo]

Hi Mak,

G.703 is initially a european standard for E1 until it was approved by the CCITT to be an international standard. So most likely, G.703 is designed for E1. Thus most of the modules for G.703 is E1. The equivalent ANSI standard is the T1.703. Though possible (one way is to map the timeslots), there are still difficulties in interconnecting T1 and E1 so better avoid doing so. As per the modules, here are a list of T1/E1 modules. And based on the specifications, product codes with G.703 means that the module supports E1 unframed G.703 aside from the standard CSU/DSU applications.

http://www.cisco.com/en/US/products/hw/modules/ps3129/prod_module_series_home.html

Thanks and Regards,

Albert