Linksys ATA box and line length 1

[doktor]

Hello!

I was asked by our engineers how long a line you can install between the Linsys ATA box (model PAP2T) and an analogue telephone.
We think that it will work with a line of ½ to 1 km, but ask just to be shure.
The Linksys ATA box converts VoIP (SIP) to 2 analog ports (FXS). (Linksys PAP2T 2 Port VoIP FXS ATA)

///doktor

 

[Sympology]

Not sure on this model, but a Cisco one has these stats

5 REN 200 ft (61 m)
4 REN 1000 ft (305 m)
3 REN 1700 ft (518 m)
2 REN 2500 ft (762 m)
1 REN 3200 ft (975 m)

Only the truly stupid believe they know everything.
Stu.. 2004

 

[doktor]

Thanks StuReeves!

I guess that 1-5 REN is the cable quality (thicknes)?
We normally use the thicknes (AWG) for the wire when we hand out recommended cable lengths...

///doktor

 

[Sympology]

REN is Ring Equalivalent Number.

All devices on a phone line will have a rating.
Most phones will be REN1, answer machines are sometimes REN2.

So if you have 1 phone (1 REN) & 1 answerphone (2 REN) you have a total of REN3.


If you exceed the REN, then they will start to play up (not ring, poor sound).


So on a 305m line you could have up to 4 phones.

Most phones should have the rating on a label somewhere.

Only the truly stupid believe they know everything.
Stu.. 2004

 

[doktor]

OK Stu!

I can see your point now.
Thank you for your help in this case!
///doktor

 

[jerryreeve]

A lot of the newer phones have REN's lower than .5 so you might be able to push the envelope even further. of course there are still the line drivers to really push the distance.

----------------------------
'Rule 29', "The enemy of my enemy is my enemy's enemy. No more. No less."
----------------------------
JerryReeve
Communication Systems Int'l
com-sys.com

 

[SYQUEST]

The REN spec has only to do with ringing nothing else. I took a look at the Linksys documents on the PAP2, and the phone line specs are very lacking. Since this is a very inexpensive device it is probably very limited. Ohm's law applies here for DC voltages. The manual says not to use any wire or cable smaller than 26AWG, and the larger the better. Since no loop voltage was specified in the documents, you will have to measure at the jacks to find this item. The power requirement listed for the PAP2 says 5.0vdc @ 2.0Amps. I can tell you one thing, you won't get very far on copper with that kind of design. With a DC-to-DC converter or switching power supply the loop current is probably very small.

If you really want to use this device on 1km length of cable you will probably have to supply a loop extender and/or a voice frequency repeater (DLL) and a -48VDC power supply.

....JIM....

 

[doktor]

Hi Jim

I told our engineers not to expect more than up to 300 meters of line length with this Linksys PAP2T device, using 26AWG.
Anyway, the Linksys ATA box (PAP2T)for can be placed near the analog phone, just by "pulling" the LAN cable near it.
///doktor

 

[jerryreeve]

Jim, When I needed to push an analog phone out beyond the normal I would bond together 2 or more pairs to give you a bigger cross section (apparent size of wire) this could get you further out but you will not find anyone willing to tell you "Yess this will work" you have to just try it out and see if you can get it to work.

Normally the specs given by the design engineers have enough "slack" in them to let you push out the limits a bit.


----------------------------
'Rule 29', "The enemy of my enemy is my enemy's enemy. No more. No less."
----------------------------
JerryReeve
Communication Systems Int'l
com-sys.com