Voice
Communication in Business Volume 2
Essays on telecommunications,
1981-2002
Of
course, some people and most system designers do not know what a 1A2
key system is, or how it is used. Thus, as a follow-up to the small
PBX article, I wrote this for the July-August, 1987, issue of
Business Communications Review.
The
exponential 2 in the title is a joke based on a series of ads being
run at the time announcing the merge of Burroughs and Sperry into
Unisys, exponentially more powerful than its component parts.
The Power Of 1A2
(Business Communications Review, 1987)
I must have gotten ten
calls in the last two or three months asking for the minimum feature
list a PBX must have to be competitive. Not one caller asked what
features would be needed to blow the competition away...just what
are the minimum features it takes to get by. Unfortunately, this is
not an unreasonable attitude, considering the vastness of the
feature lists of established PBXs, and the importance of initial
cost to many who evaluate proposals. Under competition, you cannot
afford to innovate and minimize cost at the same time, particularly
if you're the new kid on the block.
But as the sophisticated
know by now, lengthy feature lists tend to be paper tigers. Few
people know how to use more than two or three features, and even
fewer actually use them. So if we were to talk about the best of all
possible worlds, how should we actually approach features to make a
PBX valuable to the customer? Different kinds of features need
different approaches, but the one I have worked out for station
features seems to to be headed in
the right direction. It is based on the following general idea:
If you have to train the
station user,
the system is designed WRONG.
I can already hear the
shrieks of dismay. Training is one of the most important aspects of
putting in a new PBX. You HAVE to train the users to make full use
of the incredible sophistication in their telephone system. Without
training, anarchy will reign.
I have very little
sympathy for such attitudes. To me, the purpose of a sophisticated
system is to make sophisticated users unnecessary. To suggest what
can be done, consider hunting. When my line is busy, an incoming
call goes to my secretary automatically. Neither of us have to do
anything...it just happens. And, at a more sophisticated level, we
have automatic route selection: the user dials 9 plus the outside
number. The PBX, if it is set up properly, decides whether or not
that particular person can make the call at all, and if so, what
facilities he or she is permitted to use. Then it places the call.
The user need know nothing about networking, WATS lines or choosing
the right access code for the proper facility to the desired
destination. Just dial 9 and go.
Most of the station
users working for my clients are NOT professional telephone callers.
They are office workers, salesmen, administrators, accountants,
engineers, managers, executives. Their purpose is to do whatever
they are hired to do. The purpose of the telephone system is to help
them do it. As unobtrusively as possible. They should not have to
have instruction on how to use their phones, just as they no longer
need detailed instructions on how to make long distance calls with
ARS.
But how can a PBX with a
thousand features possibly be easy to use? There is a simple
approach. Just be sure its electronic telephone sets work like the
1A2 key sets of yesterday, and you are home free. The 1A2 key system
evolved over 30 years to meet the needs of station users; study its
design and operation and you'll see what users have voted for with
their dollars for decades. Indeed, the amount of 1A2 still in use
behind PBXs and, to an even greater extent, Centrex, shows that it
has to be doing something right. In particular, 1A2 gives users
access to several lines rather than one, and that is the secret of
its power.
Station Features
Between 1975 and 1980,
the makers of electronic PBXs, completely unable to compete with
existing electromechanical systems on the basis of price, started
developing features, mostly based on inexpensive memory in their
control computers, to make their systems seem like more for the
money. Then, as a result of this profusion of features, they offered
the customer the opportunity to get rid of "all that expensive 1A2
key equipment," replacing multi-button sets with single-line
(residential) telephones.
In the worst of such
systems, the customer had to learn to differentiate between a great
variety of call progress tones to figure out what the system was
doing, and then had to remember dozens of "feature codes," keyed
into the system after a "hook flash" to tell it what to do. In
short, the user had to become a telegraph operator to make a phone
call. And he or she couldn't do it without extensive training. And
retraining. And retraining.
The logical way to
correct this problem, now embraced by most PBX manufacturers, is to
provide proprietary telephones which look sort of like 1A2 key sets,
and SOMETIMES behave sort of like them. But all too often, they
retain flash and feature code thinking. That is, they emphasize
single button activation of single-line features rather than the
multi-line access that came naturally with 1A2. Such phones have
sometimes backfired on PBX manufacturers because the continuing
decline of computer and memory costs has made it easy for
independent manufacturers to add inexpensive repertory dialers to
conventional phones. When these dialers are programmed to send a
hook flash, detect dial tone, and then send a one, two or three
digit feature code, they do just what the proprietary sets do and
often at half the price. The repertory dial approach is not a bad
one. In many instances, it is all that is needed. But there are a
good many places where it works no better than the conventional
single-line sets it was designed to replace.
Northern Telecom
pioneered a suitable solution with the original SL-1 set in 1975
which could duplicate the functions of 1A2 while using more
appropriate modern technology. AT&T followed shortly thereafter with
electronic sets for the Dimension family, and Fujitsu, then American
Telecom, made a line card to support an electronic key set from ITT.
Most other electronic sets of that period, including the Rolm ETS
100 which could pick up three lines, put more emphasis on single
button activation of single-line features. It was not until the
1980s that electronic sets designed to work with parent PBXs to
emulate the multi-line approach of 1A2 became generally available;
then, curiously enough, the ROLMphone series moved more toward
multi-line pickup, while AT&T's electronic sets for its digital PBXs
took a strong turn toward buttons primarily for feature activation
on a single line.
A 1A2 Example
Let's consider an
example of 1A2 operation. Suppose the boss is talking on line one
and the secretary is on line two. A third call comes in on line
three. The secretary puts line two on hold with the HOLD button,
selects line three by depressing its button (or key, in telephone
terminology), and greets the new caller. The call is for the boss.
The secretary puts line three on hold, gets on the intercom, and
signals the boss who hears a distinctive beep. The boss can now put
line one on hold to answer the intercom, get the appropriate
information from the secretary, and return to line one or take the
new call on line three, simply by pushing the appropriate button.
Just try to do that with a single-line 2500 type set! Or, for that
matter, with some of the feature-activating proprietary sets
presently available.
To make things easy for
the station user, 1A2 buttons are illuminated, and the status of
their lines is known instantly by just looking. If the line lamp is
off, the line is idle. On steady, in use. Flashing one way, on hold,
and flashing another way, ringing. All this sounds complicated when
you read it, but most people can handle it, almost intuitively,
without any training at all. To maintain that level of non-training
is our basic objective with new station sets and features.
Two More Scenarios
The above scenario is
usually referred to as "boss-secretary." Let’s look at a couple of
others: principal and assistants, and what AT&T calls "car parts"
but is actually much more general. In "car parts," we have one phone
at the parts desk in an auto agency, and several other phones back
in the parts room and perhaps out on the service floor. When
somebody calls in for a part, the parts clerk answers and, after
learning what part is needed, puts the calling line on hold. The
line starts to blink at its appearance on the several phones. The
parts clerk goes back to find out if the desired part is in its bin
and, when the situation is clear, picks up on the nearest phone by
simply depressing the held line's button and reports to the caller.
This approach can also
be used in any small group where all the line numbers have their own
buttons on each phone. Suppose, for instance, I am deeply into zip
terms and practice MBWA (management by walking around). How does my
secretary, or the receptionist, or whoever answers calls, find me?
Maybe by paging. The answerer puts the call on hold and calls me
over the paging system. "Mr. Goeller, pick up line 14." Then I,
wherever I am, go to a phone, push the button for line 14 (which is
blinking suitably as a clue), and greet the caller. Notice how much
easier this is than having the call "parked" on a parking orbit by
the original answerer, and then having me pick up a phone, get dial
tone, dial the pick-up code (assuming I remember it), and then the
parking orbit number. Parking orbits are often hard to identify when
parking the fourth or fifth call.
With "principal and
assistants," we have several assistants in a bull-pen area with a
boss nearby in a private office. The assistants each have their own
extension, and those extensions may or may not be in hunt, depending
on circumstances. But all the assistants' extensions appear on all
phones, as in "car parts" above, so that anybody can answer for
anybody else, and know exactly which phone is ringing and then
answered. The boss, of course, can pick up all the assistants'
lines, but will probably have a private line, or a boss-secretary
pair to which the assistants cannot connect by a simple button push.
The idea here is that the assistants usually deal with the incoming
calls but, when they get in over their heads, they use the intercom
to call the boss who bridges on to help out. Note that "bridging on"
in 1A2 simply involves pushing down the assistant's extension button
and joining the conversation. This, of course, is a conference call,
and was the most common way of making conference connections (we
even do it at home, when the kids pick up on the bedroom phone while
we use the one downstairs to talk to Grandma).
Of course, SOME of the
above operations can, indeed, be done with single line phones,
switch-hook flashes, and magic numbers, and the repertory dial
phones that simplify such operations. For instance, my secretary can
put the incoming call on hold or park, somehow identify the parking
orbit, and call me, a call-waiting beep bursting in on my existing
conversation; after flashing my switch hook to put my existing call
on hold while getting information from my secretary, I may possibly
be able to retrieve the new call with some variation of directed
call pick-up, assuming the status of my original call permits. But
this requires both me and my secretary to be trained to use the
system, retrained when we forget, and trained again when we go to
another office where a different system is used. Much harder than
pushing down the blinking button. I had a friend who, during the
course of a year, smashed three 2500 sets in frustration when his
office's key system was replaced with a small PBX.
In 1A2 key systems, each
line had a physical appearance on each phone that could pick it up.
Thus you actually did the switching in the set when you picked up
line four, and the set had a 25 pair cable (or larger) connecting it
back to the key control equipment, to accommodate each line's talk
and control paths. In new electronic systems, one has a single
talk-path and a separate control path between the PBX line card and
the proprietary set. All switching is done by the PBX switching
matrix. This makes office wiring much easier (the number of pairs in
the cable do not depend on the number of lines you want to pick up),
and it offers new opportunities, but it also produces a whole new
set of problems.
Problems Emulating 1A2
Let’s consider some of
the problems first. With 1A2, control equipment for each line was
called a KTU (for key telephone unit) and several KTUs would be
located in a KSU (key service unit). In many instances, the KSU
would be near its telephone sets; thus the multipair wiring would go
from the KSU to the sets, but only a single pair would be needed
from a KTU to the PBX or Central Office. Earlier electronic sets
attempting to emulate 1A2 typically used 2, 3 or 4 pair cable rather
than the older 25 pair cable or larger. This "skinny cable" has led
IBM, AT&T, Northern Telecom, and others to offer standardized wiring
plans, typically based on four pairs, although newer electronic sets
seldom need more than one pair plus, perhaps, a pair for power. Four
pairs seems like a lot less wire than is found in a 25 pair cable,
and it is, from set to key closet where the KSU used to live. But
from key closet to PBX, the same four pairs have to be extended
instead of one, requiring much larger riser cables than before. You
win some, you lose some.
Another problem concerns
the number of matrix ports. With 1A2 (or, for that matter, 2500 type
sets), one PBX or CO matrix port could support several "bridged"
telephones. With 1A2, it was not unusual to have, say, three lines
come in to the KSU, and five or more sets pick up the three lines.
Because each set could access each line for both incoming and
outgoing calls, and the lines could be put in hunt, the users were
often better served than they would have been with five lines going
to five single line sets. With the new electronic phones, it is not
possible to have two sets bridged onto one PBX matrix port. There
has to be a one-to-one match between set and port. Thus an inventory
to prepare for an upgrade to a new system has to count sets, not
ports on the existing matrix. Typically, the new system will have to
have 20% more matrix ports for exactly the same service. A lot of
people are still getting bopped with this one.
The numbering plan and
inventory control also need attention. With 1A2, there was no
problem in having more sets than lines (as suggested above), or more
lines than sets (as when someone has two or more lines but only one
phone). It was usual for each set to be identified with one specific
extension number until the numbers were used up, and additional sets
to be called "A Stations," and listed with one of the extensions
followed by a letter designation. Thus three phones might be named
236, 237 and 238 after their extension numbers, while two additional
sets, picking up the same lines, might be called 236A and 237A. In
this way, specific phones could be matched against equipment
listings.
With new electronic
sets, the numbering plan becomes trickier. Although there has to be
a pairing between set and port, there is no necessary relation
between port and extension number, or set button and extension
number. Because stored program systems can (and usually do) make a
line-number to equipment-number translation, any extension number
can (usually) be assigned to any port. But suppose the same
extension is picked up on several sets. Then what? Our
line/equipment translation is no longer one to one. How do we relate
button, set, matrix port and extension number? All this has to be
done in software, but different manufacturers do it differently. The
most common approach is to define a "prime line" on each set,
preserving the one to one match. Handling numbers without sets of
their own is sometimes difficult; in earlier versions of the NEAX
2400, it was not possible to have an extension number without giving
it a physical port on the matrix.
Opportunities With
Electronic Sets
Because electronic sets
usually have a single talk path and a signaling path, you do not
mean quite what you used to when you say you are answering a call on
line 243. What you mean is that the switching matrix will connect a
call that thinks it wants extension 243 to your talk path when you
pick up the phone; the control path is used to blink the lamp
associated with the button labeled 243 on your set (and maybe on
some other sets via their control paths), and ringing, either sent
down your talk path or triggered from your set by another message on
the signaling path, is announcing the presence of the incoming call.
How it works, of course is less important than the fact that you
answer the call just as with 1A2.
On an outgoing call, you
use the signaling path (usually) to tell the PBX who you are
calling, and the PBX connects your talk path through the matrix
appropriately. Your matrix port is all the system needs to know; it
really does not care which "extension number" you use. You may care
if you want the call BILLED to your prime line, but that is
accounting, not switching. If your secretary gets the other party on
the line for you (a thoroughly rude practice) and then you pick up,
simpler billing may be assured if the appearance of your prime line
on your secretary's set was used to initiate the call. It is also
easier for you to take over the call by pushing the button on your
set rather than having the call transferred to you from the
secretarial line. In either case, the switching matrix connection
will be changed from the secretarial phone to yours, but the 1A2
approach works without training.
With all this
flexibility, made possible by computer (stored program) control,
other things can happen that are not like 1A2 but are equally easy
to use. With Northern Telecom's Meridian SL-1, for instance, you can
have one line "appear" on several sets, but not return busy tone
until all sets are busy with different calls to that number. That
is, all sets receive an incoming call indication on the button
associated with the particular extension number, but as soon as one
answers and the call is switched to its talk path, the lamps on the
remaining sets go out and these sets are available for a new call.
This contrasts sharply with the traditional approach that has the
lamp lit at all appearances of a line to show that the line is busy.
But the "line" isn't busy; we just have to understand what we mean
by "line" in this case. We have a new opportunity here that did not
exist with older systems: in effect, we have a miniature call
distributor. This approach does not work well for call screening by
a secretary, but it does what it is supposed to do just fine.
We can also have several
appearances of the prime line on a given set, letting the user
handle several calls at once on a single "extension number." If you
have three different buttons labeled 243, you can use the button
positions, along with the lamping at each button, to identify
specific calls. This eliminates the need for hunting; it is a
variation of call waiting that gives you visual cues to help
understand what is going on. This approach, pioneered by Plessey and
AT&T's Horizon, is also used on AT&T's current digital systems. Note
that System 25 does not offer hunting except for conventional
single-line phones.
But now we have a new
problem. How does your secretary answer the second call coming in
when you are tied up on the first? Here we have as many answers as
we have system designers. The hard line approach says you answer
your own calls. Period. Or maybe use call forward on no answer to
some other line. However, the possibility of EITHER answering your
own calls OR sending them to "coverage" is also possible, a
variation of call forwarding all calls, but you have to push the
"send all calls" button when you do not plan to answer. In any case,
you do not have the convenience of call screening typical of 1A2. In
some systems, the call is gone from your phone and is not
necessarily identified as yours to the secretary.
System 75 originally
permitted only a prime line (with several appearances) on its
electronic sets. To add the "bridging" feature demanded by
customers, AT&T chose to give all the principal's prime line
appearances buttons on the secretary's set so that a call coming in
on extension 243, middle button, could be identified at both. A
somewhat different approach, used by Hitachi, has four buttons used
as "talk lines" associated with each set. Single buttons are
associated with the set's prime line and the prime lines of other
sets to be covered. Normally your own prime line is selected,
letting you handle four simultaneous calls. However, if another line
is seen, by its lamping, to need attention, its prime line button is
pushed to replace your prime line's appearances on your talk lines.
As we get further and
further from basic 1A2, we can explore new ideas. Buttons on other
sets can be programmed as "call forwarding targets" and/or as
indicators for directed call pick-up. In either case, such buttons
are identified with the prime line on somebody else's set, and
lamping gives you a clue as to what is happening. With call
forwarding, the other phone has to send calls to you, while with
directed pick-up, you push the button to select the ringing "line."
You can't tell the difference between this operation and depressing
the button on 1A2...until you try to announce the call to the called
party and get that person to pick up. Once the call is on your
phone, in a number of systems it is no longer on the phone
originally called.
Repertory dialing, where
a button on your phone can be used to signal the system to ring some
other phone and then set up the connection, looks like a good
possibility for the intercom operation. But the far end needs a
distinctive ring, and some means of responding to an intercom call
vs. regular call, after putting an existing call on hold.
Repertory dialing is
also useful for selecting particular trunk groups; you might, for
instance, have specific buttons for the FX groups to New York and
Chicago, and Local. Lamping would tell you if at least one trunk in
the group is free, and pushing the button would give you a trunk in
that group. Similarly, group pick-up for a given group of extensions
can appear on a particular button; lamping can tell if any station
in the group is ringing unanswered, and pushing the button can cause
the switch to connect it to your talk-path. Although not quite 1A2,
these techniques need little training. However, the problem is not
answering a call for somebody else, but screening the call and
announcing it privately to the called party, or putting it on hold
and picking it up yourself at another phone. These are the things
1A2 did best, but are also the main thing that more "modern"
approaches do not do well at all.
Because anything made of
plastic has to be cast in molds that get more and more expensive as
the number of parts increases, it is often desirable, for economic
reasons, to minimize the number of buttons on a set. One way to do
this is to use a liquid-crystal display capable of showing 40 or
more alphanumeric characters. Such displays can tell you the name
and extension number of the person calling you on an inside call,
identifying your secretary, for instance, who may be screening an
outside call. Or, with group pick-up, you will see the name and
number of the phone you are answering. With such a display, the
system can also tell you that the number you just called is
forwarding to another number, or has "do not disturb" in effect.
Such displays are helpful, and can often let you get away with fewer
buttons on your phone. But they also do two other things: they let
you handle messaging, and they provide feature prompts.
A number of systems now
have a variety of "canned messages" such as "do not disturb," "out
to lunch," "back at 3 pm," "please call me," etc., which can easily
be displayed to others. It is even possible to make up your own
messages, but entering them with a regular push-button pad tends to
be tedious. Feature prompts, on the other hand, eliminate the need
for much training, and make it possible to use some of the features
normally ignored. The Mitel Superset 4 is particularly good at this;
using software-defined buttons, which are labeled in the display
area by the system program, a variety of helps are made available in
almost all circumstances. The Telenova set not only offers helps for
its PBX but also can be arranged to do the same thing for connected
systems such as voice mail.
Testing For 1A2
Capabilities
It is hard to get a
straight answer to the question: Can your electronic phones emulate
1A2 key operation? Most vendors say they can, and many of them
actually believe it. But the chances are quite good that they do not
know what you mean, and you may not find out what they mean until
after cutover. So how can you test?
The first thing is to be
sure one set can pick up several different lines, each with its own
button, and a line can appear on several different sets, any of
which can originate or terminate calls using that particular line
identity. It should be possible to originate or answer a call on one
set and pick it up or bridge (conference) to it at another without
going through the transfer procedure. An intercom function should be
available to permit separate signaling and then conversation in
connection with call screening. Both personal (where a single button
selects the intercom channel and alerts the other party) and dial
intercom (where the channel is selected and the signaling pad used
to designate the party to alert) are appropriate in differing
situations; programming an electronic set to do either should not be
too hard. A HOLD button should be available for use with any call on
any line appearance. Lamping should make clear the status of each
call on each button. Try out the phones in a working system,
emphasizing, in particular, the boss-secretary pattern, and you can
probably tell if the system works like 1A2 or has been improved and
modernized in such a way that user training is essential before
calls can be made or answered.
Of course, there is no
reason to limit a modern telephone to 1A2 emulation. Directed and
group pickup and repertory dialing, along with messaging, calling
party, directory, and other displays are all easily added. But these
are features that should be available in addition to rather than
instead of what the customer is already used to.
Remember, the whole idea
is to eliminate the need for training. Not just initial training at
cutover of your new system, but refresher courses for long-time
employees and special sessions for each new hire. Even if the vendor
offers to do the training for free, the time the trainees have to
take away from their regular jobs is expensive. Station users should
not have to have a PhD (Phone Dialer) diploma hanging on the wall
before they can be trusted to make a business call. Organizing
systems for this objective should be a major strategy of those other
PhDs, the Phone Designers, looking for a minimum feature set.
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