Pots 66 Block
- Don’t be crazy, they use a 66 block / M-Block / B-Block as a type of punchdown block to terminate the line. Introduced in 1962, the term “66 block” simply reflects its Western Electric model number. They could also have a 110 block.
- MLP-270 1 CO Line (1 Pair) 270V 66 Type Lightning Protector For POTS lines and Analog Station Ports with Ring Voltage. The MLP-270 protects the equipment when the voltage on the pair rises above 270V. It also opens the line when the current goes over 150ma.
RJ is an acronym for Registered Jack. Registered Jack type 11 is standard for telephone use in North America and many other parts of the world. There are registered jack designations from RJ11 to RJ48.
Update an old phone system or install an efficient new one with the 66, 110 and lightning-protected wiring blocks and accessories available online at Discount Low Voltage. We offer fast turnaround on orders for in-stock items and can help you find the right product for your application. A 66 block is a type of punchdown block used to connect sets of wires in a telephone system. They have been manufactured in three sizes, A, B, and M. A and B have six clips in each row while M has only 4. The A blocks have the rows spaced farther apart and have been obsolete for many years.
Though the RJ-11 connector has a total of 6 connector positions, typically either only 2 or 4 are used.
RJ-11 connector wiring comes in two standard types. There's (A) Untwisted and (B) Unshielded Twisted Pair.
CAT5 connectors (RJ45) have 8 contacts (4 wire pairs); standard telephone jacks (RJ11) have 4 contacts (2 wire pairs). When using Cat5 use the center pair (Blue/Blue-white) in the CAT5 cable. Connect the CAT5 pair to the Red and Green on the standard phone jack.
- 1RJ-11 Plug Wiring
- 3Punch Down Block
RJ-11 Plug Wiring
The RJ-11 connector has six terminals on it. Typically, only the middle 4 are used. Line 1 is the center pair, red and green. More recently Cat5 cable is being used. In that case, the blue pairs are for the first line and use the orange pairs for the second line.
Traditional Telephony to Cat 5 Cross Reference
Table:
When polarity is concerned, the RED and YELLOW are considered the HOT or POSITIVE.
Punch Down Tool
The punch down tool is an impact tool that pushes the wire into the metal receiver of the block and cuts off the excess wire.
Punch Down Block
For a demarc is part of the Telephone System where the telephone company may use a Punch Down Block such as the 66 Block. Some installations pull a Cat.3 or Cat.5 cable in which has 4 pairs of wires and they are wrapped from top to bottom of the punch down, provide for 4 phone lines, multiple phone connections for each line all the way down the block.
Bridging Clip
Used on a punch down block to bridge the left side incoming connection to telephones or other telephony devices connected on the right side of the punch down block (via wired to jacks).
Service Loop
For a 66 block it is a good idea to have a service loop. Add an extra 2 feet and 2 inches for a service loop. The service loop is the extra wire you leave in the event that the punch down block needs rewired due to a problem with something like a broken wire. Without extra, it might be necessary for the entire drop to be replaced. The service loop is used wrapped at the bottom of the punch down block.
How to punch down an RJ11 Jack
RJ-11 is the standard for most telephones, answering machines and fax machines used in North America.
Go about an inch or more in and strip the telephone wire. Now use the string inside with the wire pairs to pull back, cutting further into the wire, exposing more. Cut off the wire right at where you applied the wire stripper. When you strip telephone or Ethernet wire the wire strippers often damage the small fragile wire. it is best to use the string to pull back, exposing more wire, and then cutting them off where the stripper was applied. It creates some waste, but it ensures you have no compromised wire. Now trim away the excess insulation which has been cut by pulling back the string and left hanging.
If using Ethernet cable, look for the blue pair. The blue pair is the first pair to use.
Pots 66 Block Bridge
If using
Apply the blue and the blue white into the RJ-11 block. It is good to keep a twist present right up to where the cable goes into the block. The two center pins on the RJ11 will be used for a single line telephone.
What Is A 66 Block Used For
Related
- Telephone RJ11 Wiring Reference