Personal tools


CPSR, August 10, 1992

CPSR, August 10, 1992




UM 365


In the Matter of an Investigation into CALLER ID and other Custom Local Area Signalling Services.

Response to US West Communication's Application for Clarification or Reconsideration dated July 6, 1992.

Comments prepared by CPSR member

Carl Page

710 SE 73

Portland OR 97215


US West is requesting that the PUC allow them to accelerate the pace of the introduction of CLASS services despite the presence of easily correctable and extremely hazardous flaws. US West also requests an $8.00 increase in the fee to establish what is today considered standard residential service.


Agreeing to US West's requests would compromise and damage an acceptable system by inserting dangerous flaws. Weakening CLASS services in the manner US West proposes would transform a marginally useful service into one that is detrimental.

Agreeing to US West's requests now would eliminate all tangible motivation for them to provide an adequate level of service in the future.

Per-Call Unblocking is needed independently of whether Anonymous Call Rejection is available. Per-Call Unblocking should be implemented with a unique code, as described in the Order.

Last Call Return is a marginally useful service that is not valuable enough to outweigh the dangerous privacy problems that would be created if it were capable of returning a blocked call.


Specific Problems with the Service that US West Proposes.

On Per Call Unblocking of Blocked Lines (PCU)

On a Unique Code for Per Call Unblocking of Blocked Lines. (PCUUC)

On Anonymous Call Rejection (ACR).

Last Call Return (LCR) Blocking.

The Discouraging $8.00 Fee Increase.

Problems with US West's Rationale.

On the Balancing Act

On Bank-By-Phone Security

On CNID as a defense against telephone harassment

On Software Changes

On the Affidavit of John T. Scott.

Should or Must.

Comments of Dr. Jeff Johnson on Feasibility of a Unique Code for Unblocking.

Comments of Erik Nilssen on the New Jersey Lawsuit on Caller ID.

Certificate of Service.

Specific Problems with the Service that US West Proposes.

There are several problems with US West's suggested services described in "Anonymous Call Rejection and Per-Call Unblocking with a Unique code". US West, in this section of the application, combined three separate issues and produced one confusing morass. This unfortunately obscures the issues surrounding each issue. The three issues are:

Whether to provide Per Call Unblocking of Blocked Lines (PCU)

Whether to provide a Unique Code for Per Call Unblocking of Blocked Lines. (PCUUC)

Whether to provide Anonymous Call Rejection (ACR).

Fortunately, it isn't necessary to tangle these issues together. Contrary to US West's claims, all of these services are valuable in their own right when considered separately.

Whether to provide Per Call Unblocking of Blocked Lines (PCU)

There are many important reasons why a caller might want to temporarily unblock a blocked line. They may be calling someone with CNID (Calling Number Identification) who chooses not to answer blocked calls, or who has Customer Provided Equipment that provides the function of ACR. The caller may choose to unblock some calls for efficiency's sake, to allow a bank teller instant access to their account, for example, or to protect the safety of the called party, such as when ordering pizza. Pizza delivery companies should be able to insist that people order from unblocked phones, and their customers should be able to comply, even those with line blocking. Pizza businesses would avoid ACR because they want to accept calls from blocked lines, so they can explain the need to unblock before ordering.

US West makes the novel claim that Anonymous Call Rejection (ACR) is the dominant reason that per-call unblocking of a blocked line is needed. Actually it is clear that circumventing ACR is not the most important use of PCU. Note that Bellcore's original design for the CLASS services does include per-call unblocking, but does not include ACR. ACR, PCUUC, and CNID provide a set of negotiating tools. Without any of these tools, the negotiation will have reduced effectiveness, but denying any of these tools will preclude effective negotiation.

Customer Premises Equipment cannot be relyed upon to provide reliable per-line blocking that can be switched on and off, as US West suggests. (page 12 line 7) Not all of the devices will have a convenient on/off switch. Once such equipment is installed, temporarily unblocking the phone for a call could require rewiring the junction box. These cheap CPE devices could also silently fail to block calls, they may be incompatible with other CPE devices, and they are unduly difficult to install in a household. They may in fact be impossible to install in most apartment buildings where the telephone junction boxes are inaccessible to residents. CPE blocking is an undue burden on phone subscribers.

Per-call unblocking of a blocked line is essential and should be offered as soon as CNID is available. Failure to provide a reasonable method of temporarily unblocking a blocked line will seriously inconvenience customers who choose line blocking. Crippling the line-blocking option in this way would have the effect of discouraging the use of line blocking, contrary to the aims of the order.

Whether to provide a Unique Code for Per Call Unblocking of Blocked Lines.

During the Commission's hearings, there was general agreement that Bellcore's original design, which uses *67 for both blocking an unblocked line, and unblocking a blocked line, is too error prone for users who are not sure whether the line they are on is blocked or unblocked. Therefore some other code is required for one of them to make blocking and unblocking reliable.

US West has already assigned a number of *NN codes, and they admit that there are two still available. We only need one. One of the two available codes should be assigned, or one of the codes U S West has assigned beyond the Bellcore standard should be reassigned. U S West's assignment of codes beyond the BellCore standard, with apparently little communication with Bellcore, is risky. Better coordination between US West and BellCore is clearly called for on this issue. US West should consult with Bellcore and come back with a better-coordinated proposal. Allowing CNID in Oregon without PCUUC would eliminate the only serious financial motivation that US West and BellCore have to provide it.

Whether to provide ACR.

The ACR service is one of the best ways to utilize the CNID system to actually obtain a reduction in the number of unidentified callers to the household, and therefore a respectable increase in perceived solitude. It should be made available as soon as possible.

Last Call Return (LCR) Blocking.

Because it is inconvenient for US West to provide blocking of LCR, they propose to offer LCR that returns all calls, even blocked ones. No compromise can be made on this important safety issue. The LCR service should not be offered if it violates the commitment to effective call blocking.

It is important to keep in mind the fact that the LCR service is not a critical one. Returning calls to people who want their calls returned is rarely a problem. When it is, LCR still cannot be relyed upon, because another call can always come in which will wipe out the number that had been saved as the last call. Unlike CNID, LCR cannot return the second-to-last call.

The costs vs. the benefits of offering the LCR service have to be compared

carefully. If the LCR service will cause the utility to violate the expressed

commitment that offering call blocking represents, then that cost clearly

outweighs the benefits of LCR.

We do have evidence provided by US West that customers have already felt betrayed when their blocked calls are available to the called party for dialing. It is surprising that this problem has been detected in service already. It will get worse as time goes on in the states that already have the defect in call blocking created by the LCR service.

Last Call Return of a blocked number is a hazardous trap to set, like leaving off manhole covers. Just because disasters would happen infrequently doesn't mean that it is responsible to knowingly set them up.

The Discouraging $8.00 Fee Increase.

The charge is a dramatic departure from the principle established in the PUC's order which provided for the continuation of existing service without additional charges. The 90 day delay in instituting the charge does not make it fair. Line blocking is the status quo, not a new service. Establishing a new charge for it is a general rate increase to the cost of establishing service, and no justification has been provided that would explain why such an increase is necessary.

It is the purchasers of the information who should pay for its distribution. The subjects of this form of electronic surveillance should not have to pay to keep their data private.

US West concentrates on the danger of diminishing the value of the CNID service (page 4 line 8). Ironically, CNID's value to the network is marginal compared to the value of the services it undermines, such as the unlisted number service. In reality this is just an additional $8.00 fee that all people who wish to preserve unlisted numbers will have to pay when obtaining new lines.

Since the number of people who choose unlisted numbers has been estimated by PacTel and others to be around 10 times the number of people who will choose CNID, it is possible that an $8.00 fee for line blocking would produce more revenue than the CNID service itself.

Line blocking must be free to Unlisted and Non-published customers who are already paying a premium for a service that will degraded by CNID availability.

Peace and quiet in the home is a fundamental need that everyone shares. The affluent will have it through CPE. Businesses will have it through their PBX. In this day and age there is no such thing as a nominal charge. Even an $8.00 charge will make it impossible for some financially strapped families to get the service they need because it would be added on to the already expensive fees for establishing service.

There is a fair way to encourage people not to block calls. If sales of numbers to CID customers is really so important, why not share the proceeds with the possessor of the number? Instead of establishing a fee for blocking, a discount for not-blocking based on proceeds from the sale of the CNID service would provide customers a fair economic incentive to avoid call blocking.

Problems with US West's Rationale.

There are several areas in US West's Application for Clarification or Reconsideration where statements are taken out of context, or are inaccurate and can lead to confusion.

On the Balancing Act

As in previous US West comments, the statement is made that a balance must be achieved between a callers anonymity and a callee's solitude. (page 3 line 6, page 6 line 21, page 10 line 17) This disheartening conclusion is reached by ignoring most of the things that happen in a typical telephone interaction in the CNID environment.

o The whole point of CNID is to allow the caller and callee to more efficiently exchange roles and share information about each other with others. An analysis that pits the "caller" against the "callee" cannot be valid because the interesting part of the interaction only begins when they switch roles.

o The CNID service by itself does not provide any significant solitude. Telephone solitude can be obtained by using tools like Selective Call Acceptance, Selective Call Rejection, Anonymous Call Rejection, and best of all, a closely held unlisted number. Caller ID gives you some control on who you choose to speak with, but doesn't reduce the number of people who can disturb the household. A gate-keeper who keeps the riffraff at bay with little supervision provides solitude. CNID is equivalent to a hazy peep-hole. You can sometimes see who's ringing, but they can just keep on ringing.

o The needs and rights for solitude that residential customers have is greater than that which businesses have.

The future solitude of a caller depends upon their ability to make calls anonymously. Solitude requires anonymity. We can have both or neither, and by attempting to balance the two we will wind up with neither.


On bank-by-phone security, (page 2 line 15) CNID provides flimsy and easily falsifiable "security" for banking which is no more in the public interest than an easily modifiable drivers licenses would be.

On CNID as a defense against telephone harassment (page 2 line 21), Mr Schrunk's comments are taken out of context and reflect confusion between CNID and other CLASS services particularly Call Trace.

On Software Changes

As software engineers, we have broad experience with user interface changes in complex systems. We find USW's cost estimates for their software changes incomprehensibly high. If SS7 switch software is really so complex as to make simple fixes so expensive, routine bug maintenance and enhancements will cost many times these estimates. Consequently, if USW's estimates for minor modifications are accurate, CPSR shudders to contemplate the costs USW will ultimately attempt to recover as other trivial problems with SS7 technology arise that need attention.

With no specific motivation it might take years to get a minor switch software change from Bellcore and the switch vendors. But they, like other competitive for-profit companies, can be pressured by holding up a large sale until they provide the right technical solution. It may turn out that when the profitability of the deal is threatened, the switch vendors will find more efficient ways to make the needed changes. If Oregon doesn't hold up CNID revenue, it really could be years before we get safe and convenient service.

On the use of CNID in domestic violence situations, (Page 15 line 7) a case where CNID was used to facilitate domestic violence is being used by the ACLU in New Jersey to test the legality of that state's implementation of the CLASS services. We expect to gather more details about this lawsuit soon.

On the Affidavit of John T. Scott.

It is too soon to expect a lot of documented evidence of problems with Last Call Return returning blocked numbers. The fact that problems were recorded in Las Vegas, and have had time to make it through the complaint tracking bureaucracy that teleco is surprising.


US West is right to signal its intent to avoid doing things the PUC has said it should do. The PUC should go right out and change those "should"s to "must"s, or otherwise make it clear that "must" is the intent.

Certificate of Service.

These comments are being mailed to the parties of UM 365.

Archived CPSR Information
Created before October 2004

Sign up for CPSR announcements emails


International Chapters -

> Canada
> Japan
> Peru
> Spain

USA Chapters -

> Chicago, IL
> Pittsburgh, PA
> San Francisco Bay Area
> Seattle, WA
Why did you join CPSR?

The need for CPSR's activities has never been greater.