E1 balanced and unbalanced.

[johnleeee]

Hello ,

could someone explain me what difference is between

balanced and unbalanced E1/PRI and how I should

configure router when I use one of them?

Is over there any configuration difference when I use balanced or unbalanced one.?

How are calls (analog dial-up)processed when comming through two PRIs installed in for example 3640 with digital mica modems.? Is over there some load balancing between them (PRIs)?

rg

jl

[lgijssel]

The difference is in the hardware. An unbalanced circuit uses a coaxial cable, the core wire carries the signal and the sheet equals ground.

A balanced circuit uses a wire pair that carries a symmetrical signal (sort of + and - if you like)

The impedance differs with the circuit: unbalanced is about 75ohm, balanced 100-120ohm.

Which one to use depends on what you need to connect to. Take care that you order the correct cable for the module, unbalanced features a BNC coax connector, balanced version terminates on RJ45.

The good thing about this: In the IOS configuration commands there is no difference.

Regards,

Leo

[lgijssel]

Regarding your second question: We are talking about telephone calls here. Load balancing is therefore a responsibilty of the provider. Once the call is delivered on one of the two E1-ports, you can only accept or reject them.

Don't forget to enter the command:

isdn incoming voice modem

Leo

[johnleeee]

Leo,

you are really a good fellow in this area.

Could you help me which pins in balanced

solution (RJ45) should I use?

rg

jl

[lgijssel]

You probably mean: I can't fucking find it?

Some more general info about these modules:

http://www.cisco.com/en/US/products/hw/modules/ps2797/products_tech_note09186a00800b1150.shtml

Connector pinout for pri-connections:

http://www.cisco.com/en/US/partner/products/hw/modules/ps2033/products_module_installation_guide_chapter09186a008010b92e.html#19815

(look under Cables, Connectors, and Pinouts)

Regards,

Leo

[johnleeee]

Hi Leo,

you are really good.....

I find it ...pins 1245

thanks

I have last question. What do you think about this..

When I have 2 PRIs installed in cisco and both are connected to PBX(two conntrolers configured on cisco)

how should I connfigure PBX? To group both E1 to one bundle or configure both separatelly.?

Question is related to ...for cisco doesnt matter from what E1 dial-up comes? If no ...Can cisco recognize from what E1 call comes?

many thanks

jl

[lgijssel]

I would say: put both lines in one group. You can then (on the PBX) set up how you want to divide the calls over both lines:

round robin gives a nice load balancing,

sequential mode loads one line fully, and only then the other one.

Both setus have their own pro's and con's; it depends on what you want to achieve.

Goodluck with your project!

Leo

[johnleeee]

Hi Leo,

first thanks for advice...I really appreciate it.

I grouped on PBX both PRI to one group(it will

work sequentially). Pls. could you approximate little for me where is difference between round robin and sequential configuration. I dont mean how does it works but what pros and cons are over there for cisco and calls itself. For example we have some tel.numbers routed from PSTN to one on our PBX and I dont know if sequential mode is sufficient for us.

many thanks in advance

jl

[lgijssel]

Round robin means: first call routed to link A; the second one to link two and so on. This means that the load on both lines will be equally spread-out. This could go a little astray when all calls on link A should last twice as long as calls on link B but that is unlikely to happen all the time and hence statistically this is a perfect system.

With sequential call routing; each call is routed to the next channel in a link. This means link A; channel 1-30 and after that link B; channel 1-30.

If you have less then 30 active calls, one router might be idle while the other one has quite a few calls going on.

I personally prefer round-robin mode for this kind of installation. Hope this brief explanation is sufficient?

Regards,

Leo

[johnleeee]

Leo,

nice explanation. It make sense.

I have one router inside which is instaled 2xPRI module.

In this case I think doesnt matter what method is

used. M I right? Should I use in this case round-robin instead sequential call routing?

rg

jl

[lgijssel]

You're right John, it doesn't make much difference then.

Leo