larry@uunet.uu.net (Larry Lippman) (10/03/89)
In article <telecom-v09i0414m04@vector.dallas.tx.us> Miguel_Cruz@ub.cc.umich. edu writes: > "This number's been busy -- " -click- less than two seconds later, > "Sir, there's talking on the line," came back from the operator. > What happened to Verify operators? Time was, you got to listen to > the operator call another operator, you could chat while the second > operator was off for 30 seconds or so doing who knows what. This > whole transaction, from dialing to hanging up, took less than 30 seconds. TSPS was designed with the intention that any or all positions so designated may have direct access to verification trunks. The No. 1 TSPS console has an illuminated non-locking "verification" key which has two possible lamp indications, steady and 120 IPM flash. The exact function of this verification key is software-defined by the TSPS operating program running on the Stored Program Control (SPC) No. 1, the TSPS processor. Therefore, the operator you reach when dialing "0" may well have the capability to perform busy line verification without requiring the services of any other operator. However, depending upon the particular central office having the number to be verified and the local TSPS serving area, a request for busy line verification may still require the services of another operator. Traditionally, most CO's have two busy line verification trunks to service the entire office. In a local DSA serving area, these verification trunks would typically be terminated on a No. 1 or No. 3 Toll Board (cord type) so that at least two positions have access to the trunks; generally, there was no verification multiple to all positions. In large cities, there was usually enough verification traffic to justify at least one operator for this purpose. In smaller DSA serving areas, operators having verification trunk access would perform other duties while not serving verification requests. In SxS CO's, the verification trunks would appear as incoming trunks which connected to a verification distributor. The verification distributor would perform the same function as a first and second selector to decode the thousands and hundreds digits of a four digit number. The verification distributor selected a connector group where the tens and units digits were dialed into a verification connector. A verification connector would provide a metallic connection to the tip & ring of the selected subscriber line; there was no ringing or busy-test function provided in a verification connector itself. A verification connector was in most cases identical to a test connector, as accessed by a local test desk in a repair service bureau. In some SxS CO's the verification and test distributor circuits were combined, while in other CO's there was a separate verification distributor and a separate test distributor. There were several variations in the method of accessing a verification trunk from the No. 1 or No. 3 Toll Board. In some cases there were TWO jacks for each verification trunk - one for dialing and one for speech - which required the use of two cords by the operator. In other cases only one jack was required for both dialing and speech. In either event, in the case of a SxS CO only the last four digits of the subscriber number would be dialed into the verification jack. In the case of a crossbar CO, the last four or five digits would be dialed, depending upon the size of the CO. Since verification trunks were also used to actually break into a connection for emergency situations, in the case of a No. 1 or No. 3 Toll Board there was usually no one-way bridging amplifier; the verification trunk circuit, if equipped with a repeater, was designed for normal two-way communication. Therefore, an operator who accessed a verification trunk had the capability of talking to the connected subscriber line merely by operating the "talk" key at the cord position. Furthermore, if a subscriber terminated a call while their number was accessed via a verification connector, the operator could usually ring their telephone by operating the cord position "ring forward" key (actually, the toll board ringing was repeated using a "test trunk ringing circuit" at the terminating CO). In a crossbar CO, verification trunks would terminate as an incoming trunk, with an incoming register being connected through an incoming register link frame to accept the proper number of digits. Upon completion of dialing into the incoming register, a completing marker equipped to handle "special features" (usually completing marker No. 0 or No 1) would connect the incoming trunk through an office test frame to a "no test" vertical in the subscriber line link frame, thereby making a metallic connection to tip & ring of the subscriber line. A situation similar to the above exists in an analog ESS office, such as No. 1 ESS, No. 2 ESS and No. 3 ESS, in that a metallic connection is made between the incoming verification trunk and the subscriber line. While no doubt similar to the above, I don't know exactly how verification is handled in a digital ESS office, such as the 5 ESS or Northern Telecom DMS-series, since there is no longer a metallic path between lines and trunks; digital ESS CO's appeared LONG after "my time in the field". :-) In a TSPS installation having direct verification capability from any position, the verification trunks as described above would now be terminated as an "operator service trunk" on the Trunk Link Network (TLN) side of the TSPS switch. Therefore, any TSPS console on the Position Link Network (PLN) side of the TSPS switch can access any verification trunk so described. As far as I know, in the original TSPS there was no means for access to verification trunks other than through a TSPS console on the PLN side of the same TSPS switch where the verification trunks were terminated. Both technical reasons and security concerns imposed this limitation. However, times have changed and resulted in a great effort toward "centralization of operator services. Therefore, it may now be possible for a centralized facility to access verification trunks in several TSPS serving areas. Whether such centralized verification access is accomplished using the TSPS RTA facility or by other means, I don't know. In general, implementing busy line verification was a low-priority function during TSPS installation; consequently, verification trunks - along with other special service functions - were often kept on a few cord-type toll board positions long after cutover to TSPS. So the point is, depending upon the local TSPS serving area, verification may or may not yet be available for direct use by the TSPS operator one reaches by dialing "0". It was not uncommon for say, outlying SxS CDO's to have their verification trunks remain on a manual toll board stuck somewhere in a corner of a TSPS facility to save the cost of providing TSPS-compatible verification trunks to these SxS CDO's - which were scheduled for upgrade to ESS, anyhow. An interesting development for busy line verification was introduced several years ago in the Bell System. WECO designed a special verification bridging amplifier which intentionally distorted speech using a simple frequency inversion technique. Therefore, during a "normal" verification request, the TSPS operator could discern the difference between speech and non-speech sounds without actually eavesdropping on a conversation. I am not certain exactly how these special amplifiers were implemented, but I believe that ANY TSPS position could verify but not eavesdrop or break in to the conversation, and only certain supervisory TSPS positions could bypass the special amplifier and break into the conversation. So, getting back to the original question, chances are the same operator you reached by dialing "0" performed the verification, all in a matter of seconds. It is also important to understand that the functions of TSPS are TOTALLY PROGRAMMABLE. The TSPS console is nothing more than lights, keys, digital displays and a 4-wire talk circuit with local sidetone; ALL of its operational characteristics are determined by software in the associated TSPS processor: the SPC No. 1, which uses either the 1-type or 3-type processor. Therefore, the manner in which busy line verification is handled has changed in the past, and no doubt may change in the future. One final point: while the local test desk facilities in a repair service bureau may also be used to "verify" a subscriber line, there is usually a rather clear distinction between this function and "operator" busy line verification. An operator who verifies a line is only trained and equipped to detect the presence or absence of speech on a line, and there is usually no presumption that absence of speech on a line so verified is an indication of trouble. By far, the most common cause of a busy line where speech is absent is a Receiver Off Hook (ROH) condition; therefore, a verification operator will usually NOT refer a line to repair service, since to do so will burden a repair service bureau with a number of false trouble reports. Also, there is a type of apparatus associated with a repair service bureau known as a Line Status Verifier (LSV). The LSV should not be confused with apparatus or facilities intended for "busy line verification". The LSV is a cordless test position for use by repair clerks in handling trouble reports. The LSV provides very simply tests for line open, foreign EMF, etc. and displays obvious faults as a code number on a digital display. The LSV is NOT intended for busy line verification purposes, and is NOT found at any DSA/TSPS facility. <> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp. <> UUCP {allegra|boulder|decvax|rutgers|watmath}!sunybcs!kitty!larry <> TEL 716/688-1231 | 716/773-1700 {hplabs|utzoo|uunet}!/ \uniquex!larry <> FAX 716/741-9635 | 716/773-2488 "Have you hugged your cat today?"