The LOD Technical Journal: File #6 of 12 Operator Service Position System (OSPS) By The Enforcer Introduction -*-*-*-*-*-* OSPS is a replacement for the Traffic Service Position System (TSPS). For a description of the TSPS console see The Marauder's article in the LOD Technical Journal Number One, File Four. The main difference between the two is that OSPS can be integrated with the 5ESS Switch itself whereas TSPS was only stand alone. OSPS uses the full capabilites of 5ESS and ISDN to provide more services. OSPS also allows for a high degree of automation and by using standard 5ESS configurations, maint. is simplified. Remote Capabilites -*-*-*-*-*-*-*-*-* By using 5ESS, OSPS takes advantage of its remote capabilites. OSPS can be used to perform any traditional operator functions and just 1 OSPS switch can handle up to 128 operator teams. This enables operators to be located at one centralized location where thousands of operators work. (To picture this, remember that MCI commercial with all the operators in that giant room) Huge operator centres can be located at great distances from their host areas. Conceivably, one huge OSPS centre could serve the entire nation. OSPS can either be made a component of a 5ESS Switch and handle various services or a single switch dealing with only toll or local calls. Control can be transferred from one OSPS to another. If there is low demand, a system crash or other emergency control can be passed on to another secure OSPS. This process is called interflow. One usage is during off-peak hours, when usage goes down for an OSPS centre to close down, and switch everything to another center. OSPS can use any number of signalling systems, with different languages or country specific requirements. Architecture -*-*-*-*-*-* Operator terminals communicate with switches using ISDN paths. This is done by connecting to positioning switch modules (PSMs). PSMs are simply the switching modules (SMs) found on 5ESS. There are numerous other SMs that use analog and digital trunks to perform a variety of services. SMs can be installed remotely in which case they are remote switching modules (RSMs) or optically remote switching modules (ORMs). Operator terminals allow operators to regulate calls and transfer data on a ISDN. Basic rate interface (BRI) is an integrated services line unit (ISLU) that connects up to the PSM. There are four main operator terminals - video display terminal (VDT) for toll assistance, basic services terminal (BST) for listing services, combined services terminal (CST) for both of these functions and intelligent communication workstation (ICW) for International traffic assistance. Knowing these terminals can come in handy when you are dealing with an operator, if you can't get an answer ask to know which terminal they are looking at. OSPS is automated as much as possible. Digital service units (DSUs) on the SMs provide digital automations when required such as requesting you to insert more red box tones (uh, coins) to continue your call. The architecture behind OSPS is based on the call processing architecture of 5ESS, and simply copies many of its functions. To originate and terminate OSPS the originating terminal process (OTP) and terminating terminal process (TTP) are used. The OTP is started when a trunk is seized, usually in the initiation of a toll call, and decides where to place the calls such as to automated billing etc. OTP also monitors the calls as its in progress and conducts billing. Should OTP move the call to an operator, it will label it as one of 128 possible conditions based on the dialled number and trunk group. TTP is started when the call goes out from the switch on outgoing trunks to enable signalling. Automatic Call Distribution (ACD) -*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*- ACD controls incoming calls to operator teams, placing them in queues if needed and directs the call depending on its condition to the right operator. At the OSPS centre, there are 128 teams, 1 for each condition. If there are no available operators ACD will place the call in one for four queue conditions. The first is ringing, the next two are announcements and the fourth is an announcement followed by a hanging-up of the caller. The ACD constantly has the status for every operator. The three conditions are made busy, busy and available. Made busy is an otherwise available operator that isn't ready to receive calls. If an operator team services more than one call type, and if one call type is queued the call with the highest "delay ratio" (the expected wait time) will get the next available operator. Supporting teams, up to 8 of which back up the principle teams act as a "reserve" if the principle ones are busy. Subject to the condition that a queue is backed up higher than the "outflow threshold" and the supporting team doesn't have a queue past the threshold either. The position terminal process (PTP) logs operator status by looking at operator inputs, calls, etc. PTP will then route the call to the operator, place it in a queue or route it to another operator. PTP -*- PTP has four models: virtual terminal (VT) - Takes keystroke inputs, checks them to see if they are legal commands and passes them on. feature model (FM) - Handles the status of the operator, if an operator logs in, it will indicate that the operator is now available. near model (NM) - Processes the operator inputs. call coordination model (CC) - Handles coordination between PTP and other operations. For example signalling between PTP and OTP/TTP. Here is how AT&T describes a typical event: . A seizure is detected on an incoming trunk, and an OTP is created. . Signalling information, such as dialled digits and the back number, is collected and analyzed; the need for an operator is recognized. . Call type is determined from the dialled digits and incoming trunk group to classify this as an OSPS call of type 1. The ACD administrator has assigned type 1 calls with serving team A as the principal team and serving team B as the supporting team. . The OTP sends a message to the ACD requesting an operator. This message identified the call as type 1 and obtains other call information. . The ACD determines that calls of type 1 are being queued. . The call is queued, and the expected delay is calculated. By comparing the expected delay with administratively specified delay thresholds, the ACD determines whether a delay announcement should be provided to the caller. . A message is sent to the OTP with this information. . The OTP first connects the delay announcement, then provides audible ring to the caller. . At this point, an operator from serving team B becomes available, and the call of interest has migrated to the head of call type 1 queue. The ACD determines that no calls are waiting in any of the principal queues for team B, and further determines that the next call in the call type 1 queue is eligible to be intraflowed to team B. The ACD informs the OTP to send the call to the available operator from team B by sending a message to the PTP in the PSM. It then marks that position as busy with a call. . The PTP, via the CC model, establishes the voice path between the caller and the operator and sends appropriate display messages to the operator terminal, via the VT model, to provide the initial call seizure information. . The customer requests a collect call from the operator who depresses the collect key and enters the number to be called. Messages are sent from the operator terminal to the PTP to relay the information. The VT model processes each incoming message and forwards the message to the near model. The near model marks the call as collect and initiates the connection to the forward party via a new CC model. This results in creation of a TTP and appropriate interswitch signalling to ring the forward party. . After the forward party answers, the operator secures agreement for the collect billing and releases the call from the position via the position release key. This keystroke is first processed by VT and passed on to the near model. The PTP notifies the OTP of the collect billing arrangements. The talking paths are reconfigured to eliminate the operator position. The two parties on the call are now speaking directly without an operator on the call. . The operator terminal screen is cleared by VT. The FM reports its status back to the ACD as available to handle another call. . At the conclusion of the call, a billing record is made by the OTP. Automation and Efficiency -*-*-*-*-*-*-*-*-*-*-*-*- OSPS is designed to be as automated as is possible. It is supposed to make as little use of human operators as can be gotten away with. When you think about it that's the result of OSPS - human operators are becoming less and less needed. If it wouldn't be for all the potential uproar, they'd get rid of all human operators entirely. They are regarded as a horribly expensive way to handle calls. OSPS allows operators comfy little terminals and pulls them out of situations where they are needed as soon as they aren't required. For example after obtaining a number for collect billing, the rest of the process - voice acceptance can be automated. Many services in the past that were separate are now combined under OSPS. For example toll and directory assistance operators had to be kept available in large numbers to handle call surges. Meaning toll assistance can be queued up, while directory assistance has available operators. Now with CST, an operator can handle both services. Data Communications -*-*-*-*-*-*-*-*-*- ISDN is used to transfer data in OSPS. External systems can also be reached for such purposes as directory assistance information. Three layers are involved in OSPS operator-switch exchanges: layer 1 - the physical layer - Gives synchronous data transmission from the terminal to the ISLU. layer 2 - the link layer - Provides point-to-point exchanges between the terminal and PSM. layer 3 - the packet layer - Is the layer 3 protocol of X.25. It's a resident virtual circuit for exchanges between the terminals and the SM's processor. Which can be used in switch virtual circuit connections to external databases. Databases -*-*-*-*- OSPS uses databases during most calls. To do such functions as check the validity of calling card accounts to prevent cancelled cards from being used. Millions of database queries take place every 24 hours. Because of the immense size of these databases, they can't all fit in 5ESS. So external databases are used. Common channel interoffice signalling (CCIS) links OSPS with external data. To link with external computers CC7 is used. Data is returned to OSPS from nodes on CCS such as the line info database (LIDB) or billing validation application (BVA). These two nodes handles your Bell's validation of all collect, third number and calling cards. The X.25 protocol is also used to connect OSPS with other databases. Each database has an ISDN directory number. So one can scan out the addresses and access them on the public PSNs. Since your RBOC doesn't want people messing around with their BILLING databases, they are put in a closed user group (CUG). ---------------------------------------------------------------------------