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14 Operator Assistance and Manual Services Early telephone networks were all manually operated. In the 1950s automatic networks began to take over, but even today they have failed to supplant all manual ‘assistance services’. In the public network human operators provide a ‘safety net’ of assistance and advice for customers, and in some private networks human PBX operators are still employed to answer incoming calls from the public network and to connect them to the required extension. In this chapter we discuss the operator assistance services which form a critical supplement to automatic switched services in meeting the high expectations of today’s telephone customer. 14.1 MANUAL NETWORK OPERATION In a manual network, the connection of caller to destination is carried out by human operator. This is done by plugging cords into individual line sockets or jacks, one jack corresponding to each possible destination user. Figure 14.1 illustrates an early manual switchboard, and Figure 14.2 a typical telephone used on such a manual network. Instead of a numbered dial there is just a cradle for the handset and a magneto generator to call the operator. The routine for making a call on a manual network is as follows. The caller lifts the handset, and rings the magneto generator by turning the handle. This has the effect of alerting the operator and lighting an opal (a light) on the operator’s switchboard (Figure 14.1). In some cases, the operator was alerted merely by rattling the cradle. This had the effect of flashing the opal. There is an opal above each incoming line jack, indicating precisely which caller wishes to make a call. To answer the request, the operator uses one of the cords mounted on the console part of the switchboard, which is pulled out and plugged into the relevant jack socket immediately below the opal. The operator is now able to speak to the caller and ask for the name of the person he wishes to call. The operator records the caller’s name, the destination number and the time of day, on a ticket for later billing of the caller. The destination party is then alerted by the operator, who rings his telephone with another hand-cranked generator. The connection 281 Networks and Telecommunications: Design and Operation, Second Edition. Martin P. Clark Copyright © 1991, 1997 John Wiley & Sons Ltd ISBNs: 0-471-97346-7 (Hardback); 0-470-84158-3 (Electronic) 282 OPERATOR ASSISTANCE AND MANUAL SERVICES Opals and z=$&.$ Destination 0 Caller Operator Schematic l I /‘ Generator signalling crank Actual Figure 14.1 Early manual, or ‘sleeve control’ switchboard is completed by plugging the other end of the cord into the jack of the destination party. In this way the pair of plugs and the cord connect the two corresponding line jacks to caller and destination. At the end of the call the caller replaces the handset, extinguishing the opal. On noticing this, the operator removes the plugs and cord from the jacks, ready for use on another call. To make calls to customers on other exchanges the operator has a number of trunk line jacks. To use them, the operator must relay the call details to the operator on the second exchange, and forward the connection. The second operator either completes the call or forwards it to another operator, as necessary. In manual networks, setting up telephone calls is highly labour-intensive, and in the early days the majority of the workforce in public telephone companies were telephone operators. 14.2 SEMI-AUTOMATIC TELEPHONY Semi-automatic telephony is the term used to describe connections which are set up by an operator across an automatic network. Semi-automatic telephony was common when telephone networks were first being automated, especially when some exchanges had been automated while others remained manual. Callers on the manual exchange, who wished to call others already connected to an automatic exchange, would have their calls connected semi-automatically by the operator. The caller would first contact the operator, and the operator would then connect the call onward using special equipment to control the automatic network rather than routing through further operators. SEM1;AUTOMATIC TELEPHONY 283 <’ 284 OPERATOR ASSISTANCE AND MANUAL SERVICES Figure 14.3 Inside of a hand generator signalling set, showing the magneto coils. (Courtesy of BT Archives) SEMI-AUTOMATIC TELEPHONY 285 Figure 14.4 Early operator switchboard. (Courtesy of British Telecom) 286 OPERATOR ASSISTANCE AND MANUAL SERVICES THE EXCHANGE AT WORK. A Museum A-side opaator answers and gets into An explanation whlch will prevent many common misunderstandings. toucll with a Hop B-side operator. who finds out if Hop 3000 is free and helps the Museum operator to connect the lina. If conversely Hop 3000 wants The telephone lines in a large city are divlded Museum 605. it i5 a Hop A-side operator who answers and gets into touch with a Mwum B-de Operator. into groups, called Exchanges. the B-s;dc. ne of M Exchange d& a Central A-side operator gets into touch with a directly only with Ringers up in that &change ; Central B-side operator. In every call. therefore, two Post Office operators. Bde with those rung-up in that Exchange : - . - - __ __ e.g Muscum 605 wants Hop 3000. In reality. d coyr.~. lhst UI four -la : 1-0 Po.1 o(Lrr rnma ud 1-0 .ancun-th.! i tk WO smhrribs. -d. We. m I .n d. d the um~d P- 06ec I&+ ud. H- llrr mea. - . . 4 S Figure 14.5 The exchange at work. An extract from an early British Post Office publication providing an explanation which will prevent many common misunderstandings. (Courtesy ofBT Archives) Ironically, in the reverse direction, any caller who was connected to an automatic exchange would have to dial a code to get hold of an operator to obtain a manual connection to any destination customer still connected to a manual exchange. Manual exchanges have progressively given way to today’s predominantly automatic networks, but even today callers resort to dialling for assistance from the operator in a number of instances 0 to call a user on a residual manual exchange (particularly in remote overseas locations) 0 to receive assistance following difficulty on an automatic connection 0 to receive the answer to a general enquiry 0 to enquire for the directory number of another user 0 to make a call to the emergency services (fire, police or ambulance) 0 to make a special service call, such as a reverse-charge call (also known as a collect call), or a personal call, etc. CALLING THE OPERATOR 287 In addition, many company switchboards and hotels still retain operators for the connection of incoming calls to individual extensions or hotel room numbers, despite the fact that direct diul-in (DDI, also direct inward dialling, DID) nowadays makes direct dialling possible. 14.3 CALLING THE OPERATOR If all we want is to get through to the operator and tell him we need assistance, the effect of cranking the magneto is very much the same as dialling the right number on an automatic network. On a sleeve-controlled switchboard (one using plugs, cords and jacks, as illustrated in Figures 14.1 and 14.4), incoming calls are indicated to the Figure 14.6 Switchboard operators at work. A picture giving an idea of the tangle of hands and leads - the frenetic operation of manual exchanges. (Courtesy of British Telecorn) 288 OPERATOR ASSISTANCE AND MANUAL SERVICES operator by lighting the opals. In modern ‘cordless’ operator switchrooms the call is administered by call queueing equipment or automatic call distribution (ACD) equipment. This equipment stacks up calls in the order in which they are received, and allocates them to telephone operators in the switchroom as they become free from dealing with previous calls. Operators simply press a button to indicate that they are ready to handle another call. While waiting in the queue for an operator to become free, the caller may hear ringing tone, or may instead be given a recorded message, something like ‘this is the assistance service: an operator will deal with your enquiry shortly’. Recorded messages have the benefit of confirming that callers have ‘got through’, giving reassurance that they are not waiting in vain. The recorded message also allows callers who have accidentally dialled the number for the operator service (when meaning to dial some other number), to hang up their calls up and try again. Because connections made via the operator are multi-link rather than single link connections, special measures are required, to ensure that the end-to-end quality of the connection is acceptable, and to charge the customer correctly. Callers are normally connected to the nearest switchroom. This ensures that the end section connection is of the best available quality. This part of the connection (i.e. from caller to operator) is not normally automatically metered for charging purposes; the call charges are derived either from paper tickets written by the operator, or from electronic tickets produced on the operator’s computer consoles. Operator switchrooms are designed to be efficient workplaces, and staff numbers and rosters are planned to meet customers’ call demand. Just as an automatic telephone network must be provided with sufficient circuits to meet the traffic, so must the number of positions manned by operators at any given time of day match the traffic demand at that time. A useful quality target for staff providing an operator service is to aim to answer all calls within a given time (say 25 seconds), or perhaps to aim to answer 90% of calls within say 15 seconds. The latter statistic is often written in shorthand as PCAl5 = go%, i.e. the percentage of calls answered in 15 seconds=90%. PCA25 can also be used as a performance statistic (measuring the percentage of calls answered in 25 seconds), but the average caller on a public network who wants operator assistance, is not satisfied with such a long wait. There is a relationship between the measured value of PCA and the staffing level of the switchroom, the use of more staff generally increasing the PCA value. Going to one extreme, to employ a very large number of operators queueing up to answer calls would ensure almost instantaneous answer. At the other extreme, with too few operators it is the caller who does the queueing and waiting. A modification of the Erlang formula presented in Chapter 30 is called the Erlang waiting-time formula. It can be used to calculate the number of operators required in a switchroom to keep the waiting time down to a target figure (i.e. to cal- culate PCA values) 14.4 OPERATOR PRIVILEGES In the onward connection of calls, operators may be given a number of special networking privileges. They may have exclusive use of particular routes or of certain TYPICAL ASSISTANCE SERVICES 289 circuits within a route, to give their callers a better chance of getting through than normal customers (especially when the network is busy). This enables the operator to be of real assistance to the caller in cases of difficulty, and furthermore reduces the likelihood of wasted operator time spent in futile repeat attempts. Other privileges explained below include manual hold, circuit monitoring and interruption, and forward transfer. However, with the increasing development and automation of networks, and the small number of human operators available for network policing, these features are becoming obsolete. Manual hold allows the operator to hold the connection even after the calling subscriber has replaced the handset. This makes it possible to trace the origin of a malicious call in a case when a caller has given a false identity. It also prevents the caller making any further calls. This use of the facility is now largely susperseded by calling line identity (CLZ) information in automatic networks and many networks today no longer have the facility. An alternative use of the manual hold facility permits tracing the cause of faulty connections. The ability to trace emergency service calls (e.g. fire, police, ambulance) is of special importance. Circuit monitoring and interruption: sometimes the operator is given the facility to monitor or interrupt customers calls while in progress. This can be useful in investi- gating customer complaints, including account discrepancies. It can also be used to break in on conversation already in progress, when an important incoming call is received, and this would have been done historically if a trunk call was received while only a local was in progress (hence the term for this facility, trunk ofer). Forward transfer: another facility becoming largely obsolete, the forward transfer facility allows the operator who has previously established a semi-automatic connection for the call, to request assistance from the operator at the destination exchange; inter- national operators used it to provide language assistance (i.e. translation). The oper- ators might speak an intermediate language (typically French or English) between themselves and their mother tongue to their own customers to resolve any difficulties during call set-up. (Example for person-to-person calls). The desired language of assistance is indicated by a special digit called the language digit, which is inserted by the originating operator’s exchange into the called customer’s dialled digit string during the signalling at call set-up. This is discussed in more detail later in the chapter. 14.5 TYPICAL ASSISTANCE SERVICES As most calls are made automatically nowadays, operators need to provide only a range of assistance services to complement the automatic service; here are some of the more common ones. ‘Station call’ service A station call is the name given to an ‘ordinary’ call between two telephone stations, when it is made via the operator. A station call may be made (via the operator as opposed to automatically) either because the call cannot be dialled directly, or because customers prefer it, or perhaps because customers have had difficulty in getting 290 OPERATOR ASSISTANCE AND MANUAL SERVICES through. Another reason may be that the customer wishes to be rung back immediately after the call has finished to be advised of the duration and charge (ADC) (also called time and charges). ‘Reverse charge’ or ‘collect call’ service For any of a variety of reasons, callers when travelling may not wish to pay for calls themselves, preferring to transfer the charges to the call recipients. The service which does this for them is the reverse charge or collect call service. The reason for trans- ferring the charge may be shortage of change when using a payphone, or to avoid leaving ones host with a large telephone bill when staying away from home. Whatever the cause, collect call service must always be made via the operator. Before receiving a collect call, recipients are asked by the operator whether they are willing to accept the call charges. If so, the call is connected and an operator ticket records the call details in the normal way, except that the bill is sent to the recipient rather than to the caller. A similar service, self-explanatory, is also sometimes available: ‘Bill call to third party’ (this might allow a payphone caller to charge the call to his home account). ‘Personal call’ service (Also called a person-to-person call.) Sometimes callers may wish to contact particular people who share their telephone with a number of others. A caller may not want to make an automatic call and pay for a connection, but to find out that the desired individual is not available. In these circumstances it is appropriate to make a personal call, via the operator. The caller gives the operator the name and telephone number of the individual required, and the operator then makes the call and checks that the right recipient is available to come to the telephone. If so, the caller is charged from the moment when the operator allows conversation to commence. Usually either a surcharge or a higher charge per minute of conversation is levied on personal calls. If the person wanted is not available, the connection is cleared without conversation and the caller is not charged. ‘Directory enquiry’ service (Also called directory assistance.) To make an automatic call a caller must have the number of the destination telephone station. Without that number the network has no indication of what connection the caller wants. If the caller does not know it, perhaps because he has not called that particular person or company before, then one way of ‘looking-up’ numbers is to use the paper directory, issued to telephone customers. This gives an alphabetic list of the names of all customers with their numbers. However, the sheer number of customers nowadays has tempted many telephone companies to issue only a telephone directory covering the immediately surrounding geographical area. The operator directory enquiry (De) service provides a more comprehensive nationwide service. Access to the service in the normal way is by dialling an access code and waiting in a queue at the nearest directory enquiry switchroom. The operator looks up the num- ber in the appropriate paper directory or by querying a computerized directory system. When the number is found it is given verbally to the caller, who then presumably follows up the enquiry by placing a call over the automatic network. Alternatively the operator