No serial numbers on telephones: Why?

[KaiserFrazer67]

File this one under "Thoughts & Observations":

With all the talk on the forum regarding trying to decipher codes and information on old telephones, it struck me as odd that there was apparently never any attempt to serialize them.  Model codes/numbers, date codes, internal equipment codes, color codes, ringer codes, customer codes, and just about every other kind of code...  except an actual serial number; at least until very recently (probably only within the last 20 years).  I'm sure there may be exceptions, especially in other countries; but the old phones I've run across in the U.S. (so far) don't have them.

You'd think that expensive and intricate (for the time) electrical equipment which was originally never intended to be private property, but rented out to subscribers, of all things, would bear some kind of serial number; if for no other reason than to help keep track of who had what kind of equipment.  The Internet modem from my cable company has a serial number, and it is registered with them under my name that way.

Any thoughts on this?  I can't be the only one who's wondered about this.  Perhaps back in those days it was seen as unnecessary, as long as the telco had some other kind of record as to what you were issued?  Maybe it's just my reaction in our modern age where just about everything produced is serialized?

What led me to think of this is the idea that if these phones had been serialized, it might have made our tasks as researchers and archivists of telephone history a little easier...   

[Phonesrfun]

If they had serial numbers, they would have to have some way of tracking the items.  Computers that we know them today did not exist back then.  Also, they did not need to track each item. The phone companies did not sell them, they owned them and all they needed to do was just track how long various parts lasted.  That's why the Bell system dated the parts. 


If they sold the phones and tracked warranties then maybe there would be a need for serial numbers.  Besides, they were almost always refurbished and had all their parts stripped off and totally repurposed.  The concept of a single unit kind of looses its purpose for that reason too.

[KaiserFrazer67]

...The phone companies did not sell them, they owned them and all they needed to do was just track how long various parts lasted.  That's why the Bell system dated the parts...

...Besides, they were almost always refurbished and had all their parts stripped off and totally repurposed.  The concept of a single unit kind of loses its purpose for that reason too.

That makes a lot of sense, especially in light of the fact that many phones were modified at the telco to suit the customers' needs:  for instance, in the General System/AE situation, many phones were shipped without a ringer to be added later by the telco according to whether or not the customer had a private or party line.  Failed components like the receiver/transmitter capsules were frequently switched out; bad dials could be swapped out for new ones; new dials added to phones which previously had dial blanks (or in the case of Leich 901s, magnetos), etc.  I hadn't thought of that; since they were designed and built to make maximum use of interchangeable parts, assigning a serial number in that situation would be superfluous at best.

Even base codes could be rendered meaningless by a refurb, which I found out when I recently acquired a friend's wall-mount Starlite dated January of 1973.  There was a 1975-dated refurb sticker stuck right over the base code.  Upon removing it to see what the code said, I found out why they put it where they did--it was originally coded "15" for turquoise; it now bore a black case, handset and handset cord.

[unbeldi]

If they had serial numbers, they would have to have some way of tracking the items.  Computers that we know them today did not exist back then.  Also, they did not need to track each item. The phone companies did not sell them, they owned them and all they needed to do was just track how long various parts lasted.  That's why the Bell system dated the parts. 


If they sold the phones and tracked warranties then maybe there would be a need for serial numbers.  Besides, they were almost always refurbished and had all their parts stripped off and totally repurposed.  The concept of a single unit kind of looses its purpose for that reason too.

Why would they not have had ways of tracking serial numbers ? That has nothing to do with computers, and much equipment was produced using serial numbers long before computerization.
It just takes a ledger to record them.  For mass produced items, all one needs to do is record the current serial number at the beginning and end of work shifts.

Western Electric transmitters had serial numbers originally, displayed on a little metal tag right underneath the mouth piece cone.  I know that Kellogg used serial numbers on their switchboards, my cordless 1007-CC PBX has a serial number, and I have seen them on others on a nice metal serial number tag.

It also appears that the early thermoplastic 302 housings had some kind of serial numbers in addition to dates.  We have a thread here on the forum about those.

The Bell System also had serialization for documentation, manuals, drawings, descriptions, which is documented in a 1940s document available in the TCI library.

I think it was a matter of discovering which method of tracking equipment was most effective in each manufacturing situation. Equipment was certainly tracked for quality control purposes. The Bell System was world-leading in research of quality assurance, statistical process control, manufacturing efficiency, and associated aspects.  Some of the pioneering work was done in those fields at Bell Labs and WECo.

[AL_as_needed]

My two cents:

It could simply be that because the parts of most phones were intended to be replaced several times in the phones service lifespan, that there wouldn't be much advantage to serializing them or their parts. Finding a 100% date-matching phone is not as common as one would hope, so specific serial numbers across parts would not really help WE, AE, or any other entity beyond what a date code could. Date codes did however help estimate average part life as phones were serviced.

Items that are not intended to be changed often or are highly specific to individual pieces of equipment (firearm parts, engine blocks on cars etc that are intended to be custom fit specifically to that individual item) usually are serialized to keep very mechanically specific (in terms of exact machineing and fit) parts from being swapped accidentally between the same model of item.

[unbeldi]

A date code is conceptually no different than a serial number, however, date codes track batches of parts, while serial numbers track individual piece parts.

It seems that it was in general more meaningful and efficient for general manufacturing of telephones to track batches rather than pieces.  Some of those reasons include the already stated aspects of interchangeability.  In general it seems that a lot less training of personnel and overhead is needed when using dates, rather than serial numbers, as it is easy to distinguish parts that are beyond their expected service life.

However, we do know that WECo trial telephones were indeed marked with serial numbers, and those sets were in general also marked with notices to return equipment directly to the Bell Labs location in charge of the project.

[Dan/Panther]

Like many items with serial numbers, that should Identify the chassis mainly.

D/P

[poplar1]

W.E. Transmitter Serial No. 4971513