OPX (Off-Premise eXtensions), and ‘a phone in the barn’
There are two basic kinds of OPX; the simple option is a phone in the house and a phone in the barn.
The more complicated option is a phone in the house and a phone across town. The first option can be
as simple as tying the drops together at the NID on the house; the second option requires service
coordination in the CO switch. FTTP also adds additional considerations.
Occam FTTP ONT POTS ports provide enough power to serve a 160 ohm loop. This could theoretically
serve a 24 gauge copper twisted pair of 3 kf. Occam can also provide a simple lightning protector.
However, if you were to try to connect a nearby phone and a phone on a very long drop, the volume
would be loud on the nearby phone and very quiet on the distant phone. We will want to limit a copper
OPX to 1,000’ unless it is a really unusual circumstance.
There are several situations that need to be considered in determining how to best serve OPX stations
from FTTP deployments.
Option 1: A home phone and a phone in the barn, served with a simple copper drop from the NID on
the home.
This can be served just by tying the drops together at the NID / ONT onto a single ONT POTS port. The
drop to the barn needs to be grounded, typically at a (copper) NID on the barn and at the ONT itself.
But, if the copper path between the house and the barn routes back to the mainline cable instead of a
separate drop for the whole path, it may be better to use a new optical fiber and ONT at the barn than
to have to retain the copper mainline cable.
Option 2: A home phone and an office in the barn, served with a copper drop.
An FTTP ONT provides one or more Ethernet data ports. In order to achieve decent data speeds the
Ethernet service needs to be provided via “Cat 5” or better data cable, not just regular telephone
twisted pair (which is Cat 3), and even with good quality cable the maximum distance from the ONT will
be 328 feet per the Ethernet specification itself. If the service to the office site is regular telephone
cable or the distance from the ONT to the office site is further than about 200’ the best option is to put
another ONT at the office site.
It is possible to equip ADSL modems on both ends of the copper cable to the office site and it is also
possible to equip Ethernet amplifiers, but these require special equipment and set-up.
Option 3: A phone in the barn, (or another house) miles away
If the sites are some distance apart the OPX functionality comes entirely from the CO switch. Older CO
switches had some OPX functionality that softswitches can’t as easily replace, partially because an old
switch could more-or-less link two ports together whereas a softswitch has to do it in software. [A
softswitch can link two separate POTS lines but it isn’t as simple because the new protocols such as SIP
assume the endpoints – the telephones - are ‘smart’. They can’t just both be linked to the same phone
number at the line card.]
FTTP ONTs typically have two (or more) POTS ports. The two POTS ports are not linked together. A
phone connected to one port would have to dial a phone number to be connected to a phone on the
other port. Linking two POTS ports even on the same ONT has to be done at the CO switch.
Occam’s ONTs have the ability to optically ‘daisy chain’ a 2nd ONT from an initial ONT. I the main ONT
fails the daisy-chained does also, so this isn’t the preferred solution, but it does require only 1 fiber from
the CO / electronics cabinet.
The following outlines how 3 Rivers wants to handle specific situations:
In general any new OPX we place today is billed to the customer 100% for time and materials plus a onetime service order fee to hook up the service, not including any inside wiring. If this is done at the time
of an OSP construction project we will need to get a new price(s) from the contractor, if they agree to do
the work.
For specific locations we should email Larry Meyer with the location, name, and estimated requirement,
and he will pass the information on to the internal groups affected. Most likely 3 Rivers will have the
customer call in their requests to Customer Service who will initiate a job or service order to track costs,
etc. and will quote charges to them at that time. Once that happens Larry will authorize the
appropriate resident to proceed with the work, but will require Mid-State to revise or make up a new
yard plot for the subscriber to sign, or obtain an easement if required, referenced to the job/service
order number, and show the unit on the staking sheet(s).
If the landowner requests items from our engineers we can share the following info. The landowner
should call 3 Rivers to make a formal request:
1. Additional POTS-only service from existing drops: 3 Rivers preference will be to retain the existing
drop from the NID on the house. If the route is from the NID on the house to the ped and from the
ped to the OPX we need to add a note to the yard plot to retain the existing ped.
If copper cable that was to be retired will need to be retained 3 Rivers will have to decide how to
handle this. Retaining the copper might result in a reoccurring charge. It also might not be doable
until after the fiber cutover.
2. POTS-only service requiring a new copper drop from the ONT or existing NID to the requested OPX
location: the landowner will be responsible for the costs.
We can inform the landowner that they can purchase copper drop cable and even a NID from 3
Rivers and place it themselves so they will only be billed for the turn-up (and verification of proper
installation and grounding).
3. If a new fiber drop is required for an additional line and 3 Rivers has verified they can offer the
desired service: the landowner will be responsible for a monthly service charge for an additional line
but may not have to pay for the drop placement. A job/service order would be required and the
workflow as above.
a. If the customer is already paying for a separate line and needs a new optical drop, it may be
placed at no cost. It will have to be reviewed by 3 Rivers Engineering to see if it would be
workable as it is probably already being served from the CO as a separate pair.
An additional example; During the engineering phase a land owner requested to have lines run to his
workers residences so they could have phones. Our engineer thought he was requesting separate
phone service for his workers so the land owner was told he would not be charged for the drops, but the
landowner just wants OPX’s. The landowner needs to call and request this as a new service, at which
time prices will be quoted accordingly. These would have to be looked at or reviewed by Engineering to
determine if they are technically feasible.