MILESTONES IN THE GROWTH OF PAGING

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MILESTONES IN THE GROWTH OF PAGING
Ron Mercer

In an article several weeks ago, we discussed the beginnings of radio paging and the earliest pagers which appeared in the late 1950's and early 1960's. In the four decades between those early 60's and the year 2000, radio paging grew from nothing to an important public service supporting the mobile communications needs of approximately 45 million users. A question arises as to the events that contributed to this growth.
In chronological order, the following events are important milestones that shaped the radio paging industry:
From Manual Encoding To Automated Dial Access: In the late 50's, private tone only "beeper" systems installed within individual hospitals and similar organizations dominated the industry. These private systems included manual encoders that were activated by operators, often the same operators who ran the organization's telephone switchboard.
When anyone wished to contact an individual carrying a pager, they:
Called the operator and requested that So-and-So be paged.
By activating appropriate buttons or switches on the manual encoder, the operator then initiated a coded radio transmission that caused the desired pager to "beep",
Alerted by the beep, the paged party called the operator to find out who had them paged, and then called the party who had initiated the page.
In the early 1960's the Bell System developed Dial Access facilities that allowed pagers to be called directly from any telephone via the Public Switched Telephone Network (PSTN). Dial access led to the introduction of Bell System "Bellboy" service which generally covered a complete city or town and was marketed to the general public.
The Carterfone Decision: From the early 1960's until 1968, FCC regulations prohibited non-telephone company equipment from being connected to the PSTN. Accordingly, throughout that period all direct dial paging was provided only by operating telephone companies (mostly Bell Companies) and, although a number of Bell Companies offered "Bellboy" paging service, in general they did not market the service aggressively and the subscriber base grew very slowly.
Also, early Bellboy systems were interconnected to the PSTN using electromechanical (relay) Control Terminals that were based on the design of traditional telephone Central Office switching apparatus. These Control Terminals were dedicated to simple tone only service with little flexibility or optional capabilities. Among the limitations inherent in many of these systems was a fixed relationship between the internal pager addresses (later called capcodes) and the telephone numbers via which the pagers were called. If a pager became defective, as early pagers often did, a replacement pager would be provided, but the new pager would have a different telephone access number. Several schemes were implemented to reduce the negative impact of this particular limitation but all remained labor intensive and inefficient.
In 1968, the FCC issued a landmark decision, known as the "Carterfone" decision, that struck down the "non-Telco" interconnection prohibition thus opening the paging opportunity to the broader community of radio service providers known as Radio Common Carriers (RCC's).
While some RCC's had operated non-interconnected (i.e. manually encoded) paging systems during the early 60's, the ability to automate the service turned paging into a much larger enterprise and propelled the industry toward the 45 million subscribers that were ultimately served.
Early Technological Developments: In the early 1970's, the expanded opportunity created by the Carterfone Decision also stimulated several technological developments including:
Migration from AM, super regenerative paging receivers to FM super heterodyne designs;
Similar migration from Low Band (i.e. 35 MHz) radio channels to VHF (150 MHz);
Pager development by a number of manufacturers (i.e. Motorola, NEC, Bell & Howell);
Control Terminals development by several manufacturers (Acme, Amcor,) that used solid state switching and offered smaller physical size and greater flexibility including the ability to assign any phone access number to any pager.
By the late 1970's, more advanced control terminals were developed (SCE, BBL, Glenayre etc.) using microprocessor technology to provide significant feature enhancements including:
Full service assignment per pager allowing any radio channel, tone or voice service, code format, capcode etc. to be assigned to any pager,
An interface to Billing Systems that supported usage sensitive service,
Integrated Voice Mail with "message stored" notification via pager,
The Digital Revolution: Throughout the 1960's and most of the 1970's, pagers were analog devices using a number of tone signaling schemes (i.e. two-tone sequential, three-tone simultaneous, 5-tone sequential etc.). Due to the limitations of these signaling schemes, only very simple services were supported:
Tone Only (aka "beeper")service which alerted users to the existence of a message, but required the user to take other action (Often a telephone call) to actually retrieve the message.
Tone & Voice service which had the benefit of delivering a message rather than simple Alerting users to the existence of a message but, due to the inefficiencies of voice, required at least 10-15 times the airtime required by tone only service. The resultant reduction in channel capacity, accordingly, caused tone & voice to be offered only in smaller systems where the additional airtime could be afforded.
In the mid 1970's, simple tone-only service was enhanced slightly through the introduction of a second function code in each pager. Each function code produced a unique tone alert pattern (e.g. Function 1 steady tone, Function 2 interrupted beep tone, etc.). This simple technique allowed users slightly greater efficiency (Function 1 "CALL HOME," Function 2 "Call OFFICE," etc.)
In the early 1980's, Digital Encoding Formats, which were to change the nature of radio paging dramatically, were introduced by several pager manufacturers:
Motorola introduced the GOLAY digital format;
The British Post Office introduced the POCSAG digital format which was adopted by several pager manufacturers including NEC, Panasonic, Multitone and others;
Martin Marietta introduced a digital format using Manchester Coding.
Both GOLAY and POCSAG were NRZ (Non Return to Zero) digital formats that necessitated the use of specialized direct frequency modulated base station transmitters.
The Martin Marietta Manchester Code, because it was a Return to Zero (RZ) format, could function with only minor modification to the phase modulated analog base station transmitters that were in place at the time. The Martin code, however, was not only less efficient than GOLAY or POCSAG but it was intolerant of delay-spread distortion that is common in simulcast systems. Accordingly, in systems using multiple base stations to achieve desired coverage, the Martin format necessitated that calls be sequenced via individual transmitters so as to prevent overlapping coverage.
Moreover, GOLAY was proprietary to Motorola and required licensing while POCSAG was an open format that did not require licensing.
Due largely to the above factors, POCSAG became the most widely used digital format from the early 1980's until the mid 1990's when Motorola introduced the higher speed, higher capacity FLEX digital encoding format. The POCSAG format, therefore, was very instrumental in the explosive growth of paging, which often exceeded 20% per year, throughout this period.
The Influence Of Touchtone Telephony: The major advantage of any of the digital formats was their ability to go beyond simple tone only service to deliver messages, rather than simply alert users to the existence of messages, and to do so with sufficient efficiency to allow large subscriber bases to be served. Two types of display service were introduced almost simultaneously:
Numeric Display which, although primarily intended to display telephone numbers, is sometimes used to display simple coded messages (1=call home, 2=call your brother, 7= call voicemail, 9=bring milk, etc). In most cases, however, numeric display does not convey a complete message but rather directs the user to a further message retrieval action;
Alphanumeric display which displays text messages.
Inherent in the provision of any display services is the need to provide a means via which messages or other information may be entered into the system so that it may be transmitted and displayed on receiving pager screens. For numeric display service, the necessary display information can be easily entered from any Touchtone® telephone. The support of alphanumeric display, conversely, requires an alphanumeric entry device (such as a QWERTY keyboard).
Touchtone® telephony (DTMF) was derived from a series of multi-frequency (MF) signaling systems designed by the Bell system in the late 1950's that first became available as an extra cost option in the United States in the mid 1960's becoming widely used in the early 1980's just about the time that digital paging appeared on the scene.
In the United States, due to the growing availability of Touchtone® telephones that allowed callers to enter numeric calls without operator assistance, numeric display paging grew quite quickly throughout the 1980's.
Alphanumeric-display service, on the other hand, required keyboard message entry which, prior to the unfolding of the Internet, was not generally available to callers who were thus generally forced to place alphanumeric calls through an operator.
Based on the availability of input facilities, therefore, in the USA numeric display paging grew far more rapidly that alphanumeric display during the 1980's and early 1990's.
It is noteworthy that in other countries, which did not have Touchtone® telephones as early as did the US, both numeric and alphanumeric display services required operator assistance and, accordingly, alphanumeric service grew more rapidly than numeric service throughout the 1980's in most other parts of the world.
The Impact Of The Internet: In the mid 1990's, the personal computer became omnipresent and, along with the related launching of the Internet, created an enormous change in the way in which paging calls were initiated. Through the P.C. and Internet, it became as simple and cost-effective to enter alphanumeric messages as it had historically been to enter numeric messages from Touchtone telephones in the 1980's. This simplicity propelled the paging industry to its zenith around 2000 when approximately 45 million pagers were in service in the USA.
Ron Mercer

Paging & Wireless Network Planners LLC217 1st Street, East Northport, NY 11731Tel: (631) 266-2604www.pagingplanners.com