Inside Wiring

Inside Wiring typically involves an Extended Demarc

This term is greatly misunderstood.  "Extended demarc" typically means that the LEC or the Customer has extended the MPOP beyond the Smart Jack.  There are actually two demarc's  .  .  .  the LEC demarc (the MPOP) and the IXC demarc (the SDP).  Howewer, the MPOP is the default demarc.  Since an RJ48x biscuit is almost always used - almost all installs are extended demarc's.

The LEC or the Customer typically extends the MPOP.  This is because the Smart Jack usually sits in a wiring closet, and is not readily available or visible in day-to-day operations.  A small biscuit mounted on the wall of a computer room is much less obtrusive and is more convenient when connecting up user devices such as routers and PBX units.  These types of demarc extensions by the LEC or Customer may be only several feet, or several hundred feet. 

An estimated 90% of circuits use this type of extended demarc.  Therefore, there are very few installs without extended demarc's.

There is another line of thinking, that views the 10 or 20 feet within the smart jack as a normal install, and even though the LEC has extended the demarc to a wall jack near the Smart Jack.  This is a common fallacy, where only installs to far-away equipment are considered extended demarc's.  In actuality, one foot of cable between a Smart Jack and an RJ48x biscuit is an extended demarc.  Even a 1-inch cable would technically still be considered an extended demarc!  Regardless, anything over 20-30 ft is also an extended demarc - and must be aquired by the customer through the proper channels.

NOTE: For optimum performance, use minimum lengths of V.35 or RS-232 cable. This recommendation is particularly relevant if you plan to utilize these serial lines at high speeds (for V.35 cable, maximum capacity is 3.1 Mbps; for RS-232 cable, maximum capacity is 64K).  Therefore these cables are not to be used for demarc extensions.

This demarc extension can be done the LEC, the Customer, or even the IXC.

FTS2001 On-Premises Wiring

Each IXC can also offer extended demarc services, or "Inside Wiring", via 3rd party contractors.  Currently most IXC's sends these tickets to other vendors.  But if the customer wishes to have the IXC perform the inside wiring, this must be disclosed at the time of the order.

The cable that comes with the CSU/DSU will be used to plug into the RJ48x biscuit.  The standard lengths that come in the box are as follows :


Cable Length



Visual Networks




These are the lengths that come in the box with the CSU/DSU's.  Unless contracted to perform inside wiring - the provider is not required to supply longer cables that this, and typically does not.  Keep in mind that these are the cables that connect to the RJ48x biscuit.  When extended wiring is required, it is usually the wire that runs between the Smart Jack and the biscuit.  Therefore, this cable is typically supplied by the LEC or by the customer, and in some cases by the IXC's contracting vendors.

Normally, the line between the Wall Mounted biscuit and the CSU/DSU is not extended, since it is preferable to have the biscuit reside near the customer's equipment.  Therefore, the line between the Smart Jack and the biscuit is preferred for extension.

Beyond the SDP, all cables are supplied by the customer.  This includes V.35 cables for router connections, as well as CSU-to-PBX cables.