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Merlin Single Line Set

Started by Adam, November 19, 2011, 08:17:14 PM

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Adam

My AT&T expertise ends at 1A2, so does anybody know:

Can a Merlin single line set, like the one pictured below, be used on a regular analog phone line?  Or does this set require a Merlin KSU?

Thanks.
Adam Forrest
Los Angeles Telephone - A proud part of the global C*Net System
C*Net 1-383-4820

GG



Lo & Behold!, an American version of the GPO Trimphone, complete with a vaguely similar handset!

I've never seen a Merlin set like that before.  However I'm going to make a wild guess:

Merlin keyphones use what appear to be Ethernet plugs on the ends of round cords.  That Merlin single-line set you have there has what appears to be a normal RJ-11 modular plug and conventional thin modular cord.  For this reason I suspect it will work on a regular analog phone line.

How to find out:  With the receiver off the hook and held to your ear, plug it into a conventional phone jack.  You should hear dial tone within 2 seconds.  If you hear something strange that is not a dial tone, unplug it immediately.  If you hear dial tone, try dialing a number.  If you hear touchtones and the call goes through and you can speak as well as hear, chances are it's an analog phone and will work on an analog line.  Try hanging up and see if you can get a new dial tone.  That will check that the hookswitch works the same way as on any other single line set.

Next test:  Make an incoming call to it from another line (e.g. another landline or a cellphone) and see if it rings (have another conventional phone plugged into the same line so at least you'll hear that phone ring in case the Merlin phone doesn't).  If the Merlin phone rings at the same time as the other phone, it's a fully conventional single-line phone.  This is slightly risky in that 90 volts AC could damage a nonstandard device intended for a key system.  However AT&T wouldn't have designed something to be so vulnerable that it would fry from 2 seconds of ringing voltage.

If when you call it, you get a busy tone, or it makes an odd noise, unplug it immediately and try calling again, and see if your other phone rings.  The point of this being, if the Merlin phone is looking for a special Merlin ringing signal and has a low enough DC resistance while on hook, it will busy out your line when a ring comes through, and can't be used. 

With those tests you should be able to determine whether you can use this as a conventional phone.


gpo706

That's a very neat looking set, hopefully you can get it up and working.

If you do I'd quite fancy one myself for the desk.
"now this should take five minutes, where's me screwdriver went now..?"

EdT

#3
I love the look of it,  another phone to keep an open eye for.  
I love post 70's to mid 90's phones which offers the convenience and looks of modern day features while still having the pre 80's heft and build quality !

GG



That one seems to have the highly-useful combination of a Recall button (flash, for call waiting & 3-way calls) and a positive Disconnect button (longer timed break, for dropping existing call and getting new dial tone). 

I'm surprised AT&T didn't market those to the general public, though they kinda' came close with the Touch-A-Matic.  Though as someone pointed out here a while ago, if you look carefully, the Touch-A-Matic handset is slightly and subtly different to the Merlin handset and the two are not mechanically interchangeable on each others' cradles. 

Also apparently there were no black Touch-A-Matics made, and one black example that turned up was actually painted over a different color of plastic. 

OTOH, Merlin was made in a number of colors, so if they used the same range for the single-line set, there would be a bunch of colors out there to look for and document. 

paul-f

I wouldn't be too optimistic about using a Merlin set on a POTS line.

The installation instructions include the following on page 9:

- - - - -
TEST THE OUTSIDE LINES
This step is optional, but if you have a basic Touch-Tone or rotary telephone with a modular plug, you should test your outside line connections now. It can save time and frustration later.

NOTE: A MERLIN system voice terminal will not work for this test.

1. Take a basic Touch-Tone or rotary telephone with a modular plug to the
network interface.

2. Plug the telephone's modular line cord into each outside line jack, and
listen for a dial tone.


- - - - -

Using a  different phone would be unnecessary if the Merlin set could perform this simple line test.

You can find a copy of 518-600-600 here:
   http://www.beatriceco.com/bti/porticus/bell/bsp.html
Visit: paul-f.com         WE  500  Design_Line

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AE_Collector

#6
I agree with Paul re using a Merlin set directly on a POTS line. However, I have never seen one like this one and it looks way more like a POTS phone than a keyset. I'm thinking there is some possibility that it is a POTS phone marketed under the Merlin name but then again maybe it is a compact electronic keyset for Merlin system use only.

I can only think of one all inclusive test to put it to. I haven't encountered an electronic keyset yet that will be damaged by connecting it to a POTS line. Have you GG?

I did fatally wound several Nortel 39xx M1 sets by inadvertently having them connected to an Avaya PBX though. Probably just Avaya (Western Electric) getting even with Nortel (Northern Electric) after all these years.

Terry

paul-f

I suppose the only thing that could stand in the way of using the Merlin phone to test the line might be the plug size on the Merlin's line cord -- it  obviously won't fit a standard jack.

Does anyone have documentation on the Merlin sets or the nerve to give one the "smoke test?"
Visit: paul-f.com         WE  500  Design_Line

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AE_Collector

Good point Pul, a quick look at the jack in the phone (if it doesn't come with a cord) would likely tell the story. If it has the large plug it isn't likely at all to work as a POTS phone.

Terry

paul-f

#9
Things are looking up!  :)

Sorting through some photos on the hard drive, the set could be a 7101A.  It has a jack to accommodate a 6- (or 8- ?) position line cord, but only two positions are wired (see photo below).

Also found this info...

5.2 Single Line Telephones
AT&T made no single line phones for the Merlin system, though nearly every Merlin system has had the ability to connect single-line telephones. Smaller systems allowed this through an accessory device. Merlin II, Legend, and Magix provided support via 012 T/R and 016 T/R cards. A single line phone is often called "Tip/Ring T/R" because it uses only two wires, the "tip" and "ring" wires. This wiring standard has been in use for over 100 years.

Single line phones have always been of limited utility in the Merlin systems. Because of not having the fixed feature buttons and displays, users could access limited features via dial-codes. The cost of adding single line phones was also high for the early, smaller systems. (One reason for the Partner system's creation was to support single line phones more easily.) Depending on the way of attachment, single line phones could take advantage of various small features, such as rotary or touch-tone dialing, and a message waiting indicator. Some features available to single-line phones are accessed by doing a "switch hook flash," depressing the switch hook for about 2/3 of a second. Some single-line phones include a "flash" button to generate the right timing.

The AT&T 7101 telephone, designed primarily for System 25 and System 75, shared the same sleek, modern styling with the Hybrid sets described below, but used standard analog signaling. The 7101 featured a Recall button, a Disconnect button, and a message waiting light. These phones could be used on any ordinary phone line. AT&T described it as: "The Model 7101A single-line analog voice terminal is about 2-¾ inches wide, 3-½ inches high, and 8-½ inches deep. The set comes equipped with the following:
_ Handset
_ Touch-Tone Dial
_ Message Indicator
_ Tone Ringer with Volume Control
_ Two Fixed Feature Buttons
_ Recall - Used to place a call on hold and to obtain recall dial tone for Conference, transfer, and other features accessible by feature access code.
_ Disconnect - Used to disconnect one call and immediately obtain dial tone for another call."

The phone included a removable metal stand; the stand provided necessary mass to keep the phone from slipping off a table. No angle adjustment is possible; it appears that different angles were available. In order to connect or disconnect the line cord, it is necessary to remove the base. In order to remove the base, it is necessary to remove the handset cord. Wall mounting no doubt was possible, but unlike the cosmetically similar
ATL phones below, conversion probably required extra parts.


Source: http://wedophones.com/TheBellSystem/pdf/overview_merlin_phone_sytems_v5.pdf
Visit: paul-f.com         WE  500  Design_Line

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EdT

Looks like the same photos from this auction,  the seller doesn't seem to be from the telephone trade,  but he says that it has been tested,  so I would think it works on a POTS line.

http://www.ebay.com/itm/Vintage-AT-T-Black-Push-Button-Desk-Telephone-Angled-Metal-Base-/130603270719?pt=LH_DefaultDomain_0&hash=item1e688fc23f

AE_Collector

Oldphon (Jeremy) confirmed that he has one of these and that they work as a POTS phone.

Terry

GG



The mod jack on the bottom of the phone in Paul's picture, is the key to this: that's a two-contact jack, as found on conventional analog phones, rather than the 8-contact jacks (similar to Ethernet jacks) found on the Merlin digital keyphones.

The reason for the warning in the installation document, is probably to play it safe and not have to go into the detail differences between Merlin phones and then risk someone plugging a Merlin digital keyphone into an analog line. 

So yeah, it looks like convergence: that it's safe to plug this into an analog line.  But if you want to be very safe, do it while off-hook and listening in the receiver: if you don't get a plain clear dial tone within about 3 seconds at most, unplug it.

kar

Can anyone tell me where one of these phones could be purchased?  Thanks

compubit

Sorry for the long reply.

I purchased 2 on eBay to see if they'd work as an straight analog phone. The jack in the back of the phone is a standard-look 4 wire modular (standard phone line cable width, not handset nor 8 conductor larger connetor). Plugging it into my Panasonic system with a 2-wire lead results in the following: off-hook, no dial tone, nor does it break the circuit; on-hook, the phone rings (also when the handset is off-hook does it ring). Opening it up, everything's on a single circuit board - TouchTone pad is connected to the circuit board with 7 wires on a flat pin-header plug. The Recall/Disconnect button is a separate module that sits "over" the TT pad and connects with 3 wires to a separate flat pin-header plug. 

The internal circuit board has a couple of ICs on it, as well as at least 1 transistor (quick glance). I'm wondering if this phone requires a separate power source (such as is provided by a larger system switch) to operate... I'll try and trace the circuit to see if the outer pair go somewhere on the cuircuit board - for giggles I may connect to one of the row 1 ports on the Panasonic to see if the 5 volts provided gets this thing going...

Jim



On a side note, this phone only works as a desk phone - no wall-hook for the handset
A phone phanatic since I was less than 2 (thanks to Fisher Price); collector since a teenager; now able to afford to play!
Favorite Phone: Western Electric Trimline - it just feels right holding it up to my face!