tel@cdsdb1.att.com (01/23/91)
Any time we order a "Data Line" for our computers here, we are given a device to put inline between the modem and the phone jack. It is a box about 4 X 2 X 1 inches, has one two-pair modular cord to plug into the phone jack, and one modular outlet that the modem plugs into. It also has a switch labeled FLL and PROG. There is a label on the box that reads exactly as follows: Armiger & Associates, Inc. Fort Worth Texas USA Data Conn. Blk. Model No. AS-97A (1-9) For use as USOC RJ- 41S-M, 42S-M, 43S-M, RTC=41S & 36X (AA-97A & 635A) Complies with Part 68, FCC Rules My question is: What is this box, what does it do, and what do FLL and PROG stand for? Anytime I ask the techs what they are for, they have no idea. They are just told to give them to the customer. I am told that NJ Bell charges an arm and a leg for these boxes. Is that just a ploy to make money or are they useful? Thanks for any responses. Tom Lowe AT&T Bell Labs Holmdel NJ tel@hound.ATT.COM 908-949-0428
syd@dsi.com (Syd Weinstein) (01/24/91)
tel@cdsdb1.att.com writes: >Any time we order a "Data Line" for our computers here, we are given a >device to put inline between the modem and the phone jack. It is a >box about 4 X 2 X 1 inches, has one two-pair modular cord to plug into >the phone jack, and one modular outlet that the modem plugs into. It >also has a switch labeled FLL and PROG. >My question is: What is this box, what does it do, and what do FLL and >PROG stand for? Anytime I ask the techs what they are for, they have >no idea. They are just told to give them to the customer. The box is a two wire to eight wire adapter. Now don't panic, it doesn't touch the two wires themselves, but adds some other signals. It leaves tip, ring, A and A-1 alone (the center four). It does add a programming resistor -- more in a second -- and a pad optionally to the loop. In a true data circuit, you want the outgoing carrier to arrive at the CO at -10dbm. However, the loss in your loop varies by condition, length, and other factors. What the traditional modems did was output their signal at a higher level, and have the phone company measure the loss in the line and add a pad. The RJ-42,3,4,5 series eight wire jacks offer this ability by coming in flavors (values of the pad) to match possible line losses. These flavors have a resistor that an appropriate modem can use to adjust its output to the correct value to get the best signal at the CO. This is the PROG position. No pad is placed on the line itself, and the modem does the work via a resistor on two of the unused positions. In the FLL, or Fixed Loss Loop, position, a pad is placed to drop the output volume by a fixed amount, and the line is not measured. I have Bell of PA put these on all our modem lines, and they call them RJ45's. Note there are other ways of wiring the boxes, and then they have different numbers, but all the same purpose. Other numbers indicate if they support exclusion key wiring, automatic jumpering, etc. Are they worth it? Most interactive modems don't use them, if your modem has a four wire (six positions, four used) mod plug, it doesn't use them. If the modem has an eight wire modular plug, it probably does. However, some modems are loud on purpose, to compensate for long loops and the loss. These sometimes need a pad, and the FLL position provides that. However, what I like better, is if you have Bell of PA put this jack in, the line is assigned a 3NDDA number (3NDDA XXX-XXXX where x's are the phone number) Then you get Data Repair service to call instead of the usual repair service, (Yea, no more is the line ok questions, just a knowledgable person on a test board actually answering the phone) and here in Phila, a two hour response time guarantee. (And I mean that 24 hours a day. I have gotten things fixed at 3 AM). And all of that for no more per month that without the jack, only a one time charge up front. And that charge, here, used to be reasonable. I haven't done it in a while, but it was about twice the charge without the special jack. Sydney S. Weinstein, CDP, CCP Elm Coordinator Datacomp Systems, Inc. Voice: (215) 947-9900 syd@DSI.COM or dsinc!syd FAX: (215) 938-0235
johnl@iecc.cambridge.ma.us (John R. Levine) (01/25/91)
In article <16347@accuvax.nwu.edu> you write: >My question is: What is this box, what does it do, and what do FLL and >PROG stand for? Anytime I ask the techs what they are for, they have >no idea. They are just told to give them to the customer. >I am told that NJ Bell charges an arm and a leg for these boxes. Is >that just a ploy to make money or are they useful? They are useful in some circumstances. The signal loss from the CO to the customer premises varies a lot depending on the distance, condition of the wire and such. Some data communication equipment, particularly older stuff, depends on knowing the amount of the signal loss. There are two ways to handle this: Fixed Loss Loop (FLL) puts a PAD circuit in the connector block to make the total loss between 8 and 9 DB. The installer measures the loss from the CO (by calling a test number that produces a known signal) which is usually less than 8 dB and puts in a block with an appropriate PAD to bring the total loss up to spec. Programmable (P or PROG) puts a resistor into the connector block whose value depends on the measured loss. The resistor is not directly connected to the phone line but is connected to pins PR and PC (7 and 8) of the jack for the use of a PAD in the equipment plugged into it. The FLL/PROG switch unhooks the connector block PAD in PROG mode, since equipment that uses the programming resistor doesn't want its signal pre-attenuated. When the jack has both FLL and PROG with a switch, it's called an RJ41S. With the programming resistor only, it's a RJ45S. With various obsolescent arrangements that involve a telephone with a DATA button, its an RJ42S, RJ43S, RJ46S, or RJ47S. These are all the same physical data jack, but wired in different ways. If you are using something like a V.32 or Telebit modem, the data line is overkill since these modems have their own compensating circuits. Also, be sure that the installers are measuring the loss and setting the PAD and programming resistor appropriately. If they aren't, the jack is no better than a regular voice RJ-11 and, in all likelihood, the signal quality on the line isn't any better than a POTS line, either. Regards, John Levine, johnl@iecc.cambridge.ma.us, {spdcc|ima|world}!iecc!johnl
roy@alanine.phri.nyu.edu (Roy Smith) (01/25/91)
> Any time we order a "Data Line" for our computers here, we are given a > device to put inline between the modem and the phone jack [...] It also > has a switch labeled FLL and PROG. There is a label on the box that > reads exactly as follows: > For use as USOC RJ- > 41S-M, 42S-M, 43S-M, > RTC=41S & 36X (AA-97A & 635A) Personally, I think it's a crock, but anyway, here's what it all means. FLL is Fixed Loss Loop and PROG is for Programmed Loss Loop. What all that means is that you have a loop of copper wire running from the central office (CO) to your jack. Depending on the length of the loop (i.e. the distance from your building to the CO) the resistance, and hence the loop loss, will vary. In the programmed mode, inside the little box is a resistor which is used to compensate for the loop loss; the box should have come with a little package of fixed resistors; the tech who installed the box was supposed to have measured the loop loss and installed the proper resistor based on the results of his measurement. USOC is just an acronym which stands for Universal Service Ordering Code. It's telephone-speak for "part number", more or less. All of the RJ-4X-Y jacks are variations on an 8-pin data jack. According to the documentation I have, "Data configurations use jacks which incorporate components to limit signal power levels of data equipment. Data equipment with a maximum signal power output of -9dBm are not limited to data configurations."; I interpret that last part as "any modem you buy today can just be plugged into a plain old ordinary RJ-11 voice jack". I have the wiring diagrams for both the RJ-41S and RJ-41M jacks in front of me right now and can't find any differences; both have tip and ring on pins 4/5 (prog mode) and also on pins 1/2 under control of a switch and through what's called a "Pad" (FLL mode), and the programming resistor on pins 7/8; the resistor has no internal connections; I guess it's up to whatever is plugged into the jack to put it in series with some part of the modem circuitry if it wants. The note on the 41M says it's for use in multiple installations, but I don't see how it's any different from the 41S. A RJ-36X is a fancy jack with shorting bars, apparantly used for putting multiple series-connected modems on a single line; if you unplug the plug, the shorting bars just pass the signal through the jack, but somehow I'd be surprised if that's what you really have. The bottom line is that if you are using any sort of standard off-the-shelf dialup modem (212A, V.22bis, PEP, HST, etc, etc, etc) you don't need the fancy RJ-4X jack; just have them put in a plain old RJ-11 voice jack and that's it. Even better, don't even tell the installer that it's a data line, that usually just gets them confused. Come to think of it, even our four-wire LAD circuits that we run 128 kbps over using special leased-line modems are terminated in plain old RJ-11's (although, they probably have some other RJ code in that case). Roy Smith, Public Health Research Institute 455 First Avenue, New York, NY 10016 roy@alanine.phri.nyu.edu -OR- {att,cmcl2,rutgers,hombre}!phri!roy
Barton.Bruce@camb.com (Barton F. Bruce) (01/25/91)
In article <16347@accuvax.nwu.edu>, tel@cdsdb1.att.com writes: > Any time we order a "Data Line" for our computers here, we are given a > device to put inline between the modem and the phone jack. It is a > box about 4 X 2 X 1 inches, has one two-pair modular cord to plug into > ... > My question is: What is this box, what does it do, and what do FLL and > PROG stand for? Anytime I ask the techs what they are for, they have > Tom Lowe AT&T Bell Labs Holmdel NJ tel@hound.ATT.COM 908-949-0428 ^^^^^^^^^ A user will now tell how the Bell System and FCC set this mess up. Arminger and others like Suttle are all licensed by YOUR company to produce such devices. You will find corresponding WE-xxx numbers for your products that they make with AA-xxx numbers and Suttle has SE-xxx ones, too. Arminger is heavier into data related special jacks then Suttle. Anyway, this has lots of history that I will partly skip, but the simple part of it is that modems are not supposed to hit the CO with a signal hotter than -12dbm. Originally modems all were from the phone company, and THEY set the xmit level internally with dip switches. When users were finally allowed to plug in modems, a way was devised to let the jack set the signal level. Any modem worth its salt today can receive signals that my bad ears can barely hear. But when this was planned, there was a scheme devised whereby the installing phone company could install a data jack that would program the transmit signal level for a modem with an external resistor the installer would select supposedly after determining the loop loss to the CO. That is your PROG switch position. Some modems were assumed to be too dumb to be programmed, and you could run with a fixed pad that killed some signal level for BOTH transmit and receive. They were assumed to xmit at -4dbm, and the pad would cut the level to what was needed. The transmit side of this was cut to 'protect' the network, but padding the receive side was/is totally STUPID. There is a third option the modems have and that is 'permissive' mode. It is assumed that there will be at least 3db loss on a CO line, and so any modem is 'permitted' to transmit at a fixed -9dbm (to hit the CO at no higher than -12dbm). Permissive mode is what all normal modems pluging into RJ11 jacks are using. I never saw a modem ordered or equipped for FLL (fixed loss loop) operation, but there were specs on how to do it. Some of the old modems came with instructions for the telco to set the levels internally, or you set them for 0 dbm internally and used a special cord for the external PROG or FLL or PERM jack setup. If you had loss set inside and externally you would have too much. Typically the adapter cord to make a programmable modem a FLL one included the 866 ohm resistor for -4dbm needed in FLL mode, and the adapter cord for permissive mode included the 5490 ohm resistor needed to transmit at -9dbm. The cord for programmable mode simply connected the resistor in the jack to the modem. Your jack with cord, etc is probably Arminger's AA-330A Universal Data Station Adapter. The center two wires from the RJ11 cord go to the center two of the eight-wire data jack, so any RJ11 modem plugged into this could as well be just plugged in without this. Pins 1 + 2 go to the internal PAD and then to incoming T + R via that switch when thrown to FLL position. The resistor for PROG mode is across 7 + 8. This adapter's resistor is set for -9dbm, and the unit effectively converts OLD FASHION FLL or PROG mode modems into PERmissive ones and is an FCC registered device (APZ9P9-67263-AD-N the Ren is 0.0B in PROG, and the PAD makes Ren = 2.5B in FLL mode). On telco installed data jacks, I have NEVER seen different resistors installed whether the jack is near the CO or miles from it. The installers always put in just one value. In the real world now, NO ONE needs this nonsense. If you have OLD modems that need this, maybe buy an eight-wire jack and stick your OWN resistor in and run in programmed mode set for -9dbm (i.e. run it in permissive mode). Certainly don't BUY this sort of over priced factory nonsense adapter. New modems will run in permissive mode and that is fine. Use RJ11 jacks. In some areas you seem to need to order a data jack just to get a data quality line. Then get an RJ45S (the programmable jack with out the FLL switch - but they may 'provide' it by giving you the universal model that HAS the switch). The RJ41S function DOES include the FLL Pad, and typically is provided by an AA-97A (1-9) (that 1-9 is for loop loss of 1 to 9 dbs - each number you order comes with a different resistor and pad) and nine different order numbers!, and costs about $18. The AA-97B only does RJ45S (PROG) function (no FLL switch) and comes with eight resistors (one order #) and costs about the same. Those two are the same size box, but a newer jack that looks like a fat RJ11, but also takes the eight wire plugs is the AA-97B1. It also comes with the kit of eight resistors (NO resistor is used for the highest loss setting) and costs about $8. The same jack bought as a generic JACK is under $4, and you can get the resistor for -9dbm xmit (the 3db loop loss resistor) for pennies elsewhere. Use 5,490 (or near that) ohms. If you are stuck with telco installed FLL switches, TAPE them into the PROG position. NEVER use FLL, it is a dumb and obsolete idea. Remember any normal (permissive) modem plugs into an RJ11, but also works fine in the eight-wire jacks but hardly needs them. History lesson: xmit level resistor loop loss range 0 (short) 12 or more db -1 150 ohm 11-12 -2 336 10-11 -3 562 9-10 -4 866 8-9 -5 1,240 7-8 -6 1,780 6-7 -7 2,520 5-6 -8 3,610 4-5 -9 5,490 3-4 -10 9,200 2-3 -11 19,800 1-2 -12 (open) 0-1 Personally, I get data lines in on RJ21X jacks mixed in with general phone lines. The 25 pairs there come out on the AMP connector and go to MY-OWN CO quality 3 electrode gas tube + diodes lightning protection (I like Porta System's Delta series, but NTI/Cook, AT&T, and Reliable all make this sort of thing), and then it goes to modular patch or 66 punch and then to internal voice or data or whatever we need on OUR wires. Modems plug into RJ11 jacks. Period.
jdominey@bsga05.attmail.com (01/25/91)
I have a two-year old message sent out to AT&T sales regarding the proper termination for analog data lines. According to this message, "The JM8 is intended to be the standard termination for analog data services." I've also heard the JM8 described as an 'eight-pin mini-modular jack'. An accompanying list shows all the RBOCs accepting specification of "JM8" or "8MMJ". Some of the other independents - Centel, GTE, and Southern New England Tel - were still using the 42A Connect Block. This is apparently an older standard, and since the message is so old, they may well have changed since then. As a telemarketing type, I don't get to go out and see my customers. (They're mostly 500-600 miles away!) But I'm told that Bell South installers usually terminate analog dedicated circuits in a device called a 'Teleport', which provides the JM8 as well as some other options. Jack Dominey AT&T Commercial Marketing, Tucker, GA | 800-241-4285 | AT&T Mail !dominey
William.Degnan@f39.n382.z1.fidonet.org (William Degnan) (01/27/91)
On <Jan 23 15:58> Tom Lowe writes: > Any time we order a "Data Line" for our computers here, we are > given a device to put inline between the modem and the phone jack. It is > a box about 4 X 2 X 1 inches, has one two-pair modular cord to plug > into the phone jack... > Armiger & Associates, Inc. Fort Worth Texas USA > Data Conn. Blk. Model No. AS-97A (1-9) Use as USOC RJ-41S-M, 42S-M, 43S-M, > RTC=41S & 36X (AA-97A & 635A) Complies with Part 68, FCC Rules > My question is: What is this box, what does it do, You have answered your own questions. It is an AS-97A (1-9) [actually what you describe is an AA-97A (1-9)-RTC1]. It is for use as an RJ41S-M, etc. > and what do FLL and PROG stand for? Why Fixed Loop Loss or PROGrammable. > Anytime I ask the techs what they are for, they have no idea. Would they know if you _didn't_ ask them? Next time you can tell them that it is essentially the AA-97A-RTC connector, with the FLL/PROG switch located on the outside and a one foot, four-conductor line cord which is connected to the network side. The AA-97A-RTC is a data connecting block arrangement that includes an eight-position modular jack for the registered data connection and an eight-position series modular jack for a modular jack for a modular connection to other data interface equipment. See your modem manual for the manufacturer's recommendation for FLL vs. PROG. > I am told that NJ Bell charges an arm and a leg for these boxes. Is there something for which NJB _doesn't_ charge an arm and a leg? Disclaimer: Contents do not constitute "advice" unless we are on the clock. William Degnan | wdegnan@mcimail.com Communications Network Solutions | !wdegnan@at&tmail.com -Independent Consultants | William.Degnan@telemail.com in Telecommunications | UUCP: ...!natinst!tqc!39!William.Degnan P.O. Drawer 9530 | ARPA: William.Degnan@f39.n382.z1.FidoNet.Org Austin, TX 78766-9530 | Voice +1 512 323 9383