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Beginner

Auto-Mdix on WAN serial port

Hi, is it possible to enable auto-mdix on a serial port similar to auto-mdix on an Ethernet port ?

For example plugging in a straight T1/E1 cable and it will switch into a cross T1/E1 cable.

 

Lastly, is it possible for a serial port to be using a normal Ethernet cable ?

Unplugged some cables from a router serial card module and all are found to be 8 wirings, normal ethernet cables.

Any explanation for this ?  Thought serial port can only be using serial cable ?

 

Regards,

 

Desmond

 

 

8 REPLIES 8
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VIP Expert

Re: Auto-Mdix on WAN serial port

"Hi, is it possible to enable auto-mdix on a serial port similar to auto-mdix on an Ethernet port ?"

Not that I'm aware of.

"Lastly, is it possible for a serial port to be using a normal Ethernet cable ?"

The cable itself, perhaps, but likely would require custom rewiring of cable wires to connector pins. There's also the issue of cable distance and bandwidth rating, but I believe any Ethernet cable would exceed requirements for a T1/E1.

"Any explanation for this ? Thought serial port can only be using serial cable ?"

Yes, understand there's more to copper cabling that number of wires. I.e. there are some significant differences between "categories" of copper twisted pair cables, like between CAT-3 and CAT-7. (See: https://customcable.ca/cat5-vs-cat6 and/or https://www.cablesandkits.com/learning-center/what-are-cat8-ethernet-cables)

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Beginner

Re: Auto-Mdix on WAN serial port

Hi Joseph, thanks for your explanation.

 

Based on your statement

 

"The cable itself, perhaps, but likely would require custom rewiring of cable wires to connector pins"

So can I verify, if I would to plug in a brand new Ethernet cable without any modifications, will it work well as a E1/T1 cable ?

 

Or is it possible that at the patch panel side, some kind of modification was done to enable it to use normal Ethernel cable without any modification of the wiring/connector pins ?

 

 

 

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Hall of Fame Master

Re: Auto-Mdix on WAN serial port

Hello @Desmond Lee ,

 

see Table B-2 pag 3 of the following document for E1 pinout

 

https://www.cisco.com/c/en/us/td/docs/wireless/asr_901/Hardware/Guide/HW_Guide/HW_cable.pdf

 

I think the possibility to use straight ethernet cable exist but the device on the other end of the cable has to be ready to crossover the correct pins to build a working connection.

 

Hope to help

Giuseppe

 

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Beginner

Re: Auto-Mdix on WAN serial port

Hi Giuseppe, great document.

 

The serial card model is SPA-8XCHT1/E1.

https://www.cisco.com/c/en/us/products/collateral/interfaces-modules/shared-port-adapters-spa-interface-processors/product_data_sheet0900aecd8027ca10.html

 

Any idea if this card has the ability to do some kind of pins conversion ? (from Ethernet to E1/T1)

 

Thanks,

 

Desmond

 

 

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Hall of Fame Master

Re: Auto-Mdix on WAN serial port

Hello @Desmond Lee ,

it all depends from the ISDN / WAN provider NT network termination is that device that might be able to perform the E1/T1 crossover allowing you to use a straight RJ45 cable.

However, there are cases where the NT devices expects to receive two BNC cables for G.703 in that case you would need a cable converter.

Check with your service provider what you would use.

Hope to help

Giuseppe

 

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VIP Expert

Re: Auto-Mdix on WAN serial port

"So can I verify, if I would to plug in a brand new Ethernet cable without any modifications, will it work well as a E1/T1 cable?"

Don't believe so. For starters, Ethernet uses RJ-45 while the T1/E1 looks to use RJ-48C and the pin to pin connections are different too.

"Or is it possible that at the patch panel side, some kind of modification was done to enable it to use normal Ethernel cable without any modification of the wiring/connector pins ?"

If the modification was done at the pin level of the patch connectors, likely yes, otherwise no. However, the wire specs, besides pin outs, can also differ. Earlier I noted Ethernet cable specs might exceed those for T1/E1, for some categories of Ethernet cable, the converse might be true.

Maybe this will help: http://www.differencebetween.net/technology/difference-between-rj45-and-rj48 Note the summary of differences at the bottom.
Highlighted
Beginner

Re: Auto-Mdix on WAN serial port

Hi Joseph, thanks for the explanation.

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VIP Expert

Re: Auto-Mdix on WAN serial port

BTW, I'm guessing that since the RJ jacks are basically the same, and the cables looks alike, you were wondering whether you could just swap one cable for the other?