gmw1@cunixd.cc.columbia.edu (Gabe M Wiener) (05/12/89)
Hello netlanders. We're about to put in a Merlin system. Now as I understand it, the Merlin takes an RJ-21X. We're also putting in an automated alarm system with a telephone hookup that takes an RJ-31X. Qu'est-ce que c'est? Can anyone tell me exactly what an RJ-31X is? I know that an RJ-21X is one of those rectangular connectors that can accomodate up to 25 (?) dialtones. What about the RJ-31X? Thanks. -G
julian@seas.ucla.edu (julian macassey) (05/14/89)
In article <telecom-v09i0162m08@vector.dallas.tx.us>, gmw1@cunixd.cc.columbia. edu (Gabe M Wiener) writes: > Hello netlanders. We're about to put in a Merlin system. Now as I understand > it, the Merlin takes an RJ-21X. We're also putting in an automated alarm > system with a telephone hookup that takes an RJ-31X. Qu'est-ce que c'est? > Can anyone tell me exactly what an RJ-31X is? I know that an RJ-21X is one > of those rectangular connectors that can accomodate up to 25 (?) dialtones. > What about the RJ-31X? Thanks. OK, let's start with the RJ-21X, because it is not "one of those rectangular connectors". The rectangular connectors are known as "Amphenol" connectors, although they may also be made by Cinch, Amp or other people I have not heard of. They are known in FCC Rules and Regulations Part 68 as "50 Position Miniture Ribbon Plug". Now you know why they are called "Amphenols" An RJ21X is a 66 block that is used as the "Demarcation Point". This is the point at which the telco hands the lines over to the customer. This is a "split" block using bridging clips so each line can be disconnected at this point for trouble shooting and finger pointing. Most RJ21X blocks have an Amphenol jack on the side so you can save time etc by plugging an Amphenol plug in that leads directly to your PBX or Key system etc. This saves having to run individual pairs for each of the possible 25 trunks. Most RJ21Xs have less than ten trunks on them so usually the trunks are punched down with regular wire. The RJ21X description in Part 68 states a few things which are not common practice. It does not mention the 66 block and states that the telco will consecutively wire the lines - not true with Pacific Bell, they put them on any pair you state, i.e. PBX lines 1 - 15, FAX line 25, Modem line 24. When Part 68 was written, the use of "RJ21X" as a demarcation device was not common, hence their description of typical usuage "Traffic Data recording equipment". An RJ31X is an 8 position jack with a few extras. They are used mostly by alarm companies. When used by alarm companies, they are wired so that a line runs through them in series. What this means is that the pins have special shorting bars across them. For example: Tip comes in on Pin 5 and via the shorting jack leaves on Pin 8. Ring comes in on Pin 4 and leaves on Pin 1. Now when the alarm company comes along, they plug their alarm dialer (The one that calls the alarm center or the fuzz) into the RJ31X. The shorting bars are now lifted and Tip and Ring runs through the dialer. When the alarm goes off, the dialer will disconnect the customer side of Tip and Ring and dial out on the Telco side (Pins 4 & 5). Note: Many alarms sense voltage on the line and if you randomly unplug the RJ31X, the alarm will go off and make more noise than a heavy metal concert. Usually, you put the alarm on the least used pair, often the last or your FAX line. Note that the RJ31X is an 8 position modular device, sometimes called a "business jack". Regular phone jacks are 6 position modular devices. The same jack will change its number depending its usage. When the same jack is wired the same way, but used for an automatic dialer (Not an alarm dialer) it becomes and RJ32X. When used with a "Data Set" (Modem) it becomes an RJ36X. If it is for a modem with "programming resistors", but no shorting bars, it becomes an RJ41S If you are feeling confused by now, don't worry. If you have to install an RJ31X, they usually have instructions and drawings in the box. If all else fails, you may be lucky to get an alarm installer who understands these things. Yours -- Julian Macassey, n6are julian@bongo ucla-an!denwa!bongo!julian n6are@wb6ymh (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495
dave@rutgers.edu (Dave Levenson) (05/18/89)
In article <telecom-v09i0164m01@vector.dallas.tx.us>, ucla-an!denwa!bongo! julian@seas.ucla.edu (julian macassey) writes: > OK, let's start with the RJ-21X, because it is not "one of those > rectangular connectors"... > An RJ21X is a 66 block that is used as the "Demarcation Point". Actually, the code RJ-21X refers to the "Amphonol" 50-pin miniature ribbon connector, and not to the "66-block" with which it is often associated. In a "by the rules" RJ-21X installation, the customer equipment is required to be attached by an "Amphonol" which mates with one supplied by the telco. In the real world, the RJ-21X provided by most telcos is connected to a 66-block which contains the demarcation straps described in Julian's posting, and is then connected the service-entrance cables at the station-protector. A lot of premises equiment installers will punch down wire pairs on the telco 66-block, and ignore the "Amphonol" provided. I have one customer, however, where the 66-block is under lock and key, and the RJ-21X is the only connector accessible to the customer. (The installers promptly installed their own 66-block and cabled it with an "Amphenol" to the '21X!) -- Dave Levenson {uunet | rutgers | att}!westmark!dave ...the man in the mooney
jbh%mibte.UUCP@mailgw.cc.umich.edu (James Harvey) (05/23/89)
In article <telecom-v09i0168m06@vector.dallas.tx.us>, westmark!dave@rutgers. edu (Dave Levenson) writes: > In article <telecom-v09i0164m01@vector.dallas.tx.us>, ucla-an!denwa!bongo! > julian@seas.ucla.edu (julian macassey) writes: >> OK, let's start with the RJ-21X, because it is not "one of those >> rectangular connectors"... >> An RJ21X is a 66 block that is used as the "Demarcation Point". > Actually, the code RJ-21X refers to the "Amphonol" 50-pin miniature > ribbon connector, and not to the "66-block" with which it is often > associated. In a "by the rules" RJ-21X installation, the customer > equipment is required to be attached by an "Amphonol" which mates > with one supplied by the telco. This is true. The customer is NOT supposed to use the punchdown terminals. > In the real world, the RJ-21X provided by most telcos is connected > to a 66-block which contains the demarcation straps described in > Julian's posting, and is then connected the service-entrance cables > at the station-protector. A lot of premises equiment installers > will punch down wire pairs on the telco 66-block, and ignore the > "Amphonol" provided. I have one customer, however, where the > 66-block is under lock and key, and the RJ-21X is the only connector > accessible to the customer. (The installers promptly installed > their own 66-block and cabled it with an "Amphenol" to the '21X!) This is the standard way of dealing with the Amphenhol (why do people insist on calling it a 50 pin Centronics?) connector. -- Jim Harvey | "Ask not for whom the bell Michigan Bell Telephone | tolls and you will only pay 29777 Telegraph | Station-to-Station rates." Southfield, Mich. 48034 | ulysses!gamma!mibte!jbh