1906 - North Pittsburgh
Telephone was founded. The first two manual exchanges were Richland (based
on modern-day Bakerstown-Warrendale road) and Mars (based in Mars Borough).
1908 - 258 phones
were in service.
1909 - Gibsonia
manual exchange was created on Route 910 (Gibsonia Road)
1910 - Wexford
manual exchange was created.
Curtisville manual exchange was created.
1923 - People's
Telephone Company of Mars was purchased.
1930 - Gibsonia
office was remodeled
1936 - Richland
manual exchange retired, customers moved to Gibsonia or Mars
Cooperstown exchange was created (this is assumed to be a dial
1945 - Start of
construction of new dial exchanges for Gibsonia, Wexford and Criders
1949 - The
Vinewood exchange was created to serve Cranberry, Bradford Woods and
Warrendale (this is assumed to be a dial office)
1951 - Dial
telephone customers were accessable by the new DDD (Direct Distance
dial) network experiment at Englewood, NJ. The central offices that
were accessable were Gibsonia, Cooperstown, Wexford and Vinewood
(later called Criders Corners).
1953 - Saxonburg
Telephone Company was purchased.
1954 - Freeport
Telephone Company was purchased.
1954 - Used
microwave transmission systems.
1959 - All
exchanges were converted to dial service (all Automatic Electric
Step by Step). First independent to completely go dial telephone.
Dial Service to early 1980s
1962 - 19,350 telephones in
1977 - In April 1977 (according to the
picture of an ash tray that was sold on the Internet), NPT installed an
Automatic Electric #1EAX (Electronic Automatic eXchange)
at the Gibsonia headquarters. The #1EAX was invented in 1972 as a Class 5
end office and was later modified to perform Class 4 tandem functions. The
#1EAX was AE's attempt at an (analog) electronic telephone switch, similar
to Western Electric's #1ESS (Electronic Switching System, circa 1965). NPT's
implementation of their #1EAX was both Class 4 and Class 5 functions.
Ash Tray depicting the cut over date of the Gibsonia
The strange part of their
implementation was that NPT continued to use the Step by Step switch that
was already in service. The Step by Step served the 2, 3 and 9 thousand
blocks, while the #1AEX served the other thousand blocks. The Gibsonia
SxS also served as the tandem for the other Step by Step switches in the
North Pittsburgh territory. This "split system"
arrangement is quite rare and lasted until June 1987 (see later on
this page). It is believed that they started with
the Step switch, and when they outgrew it, they installed the #1EAX switch.
1978-1979 - The Wexford and Criders Corners (Cranberry Township) exchanges
were replaced with second-generation Automatic Electric #2EAX switches
(still analog, more like the Western Electric #2ESS & #3ESS switches).
These switches used the #1EAX as their direct tandem and not the Step by
Step switch in Gibsonia.
Status in Early 1980s
1982 - The status of
North Pittsburgh was as follows:
Gibsonia had both the Step by Step and #1EAX switches (on the same prefix!), Wexford and Criders
Corners were #2EAX, and the rest were Step by Step.
The chart below shows
the arrangement based upon prefix, ratecenter name, the actual areas
served, and the switch type. Note that the 443 (Gibsonia) central
office code (prefix) had both the Step by Step and #1EAX switches.
Note: At this time, the
Saxonburg exchange had two distinct switches.
The main exchange was in Saxonburg, the other in Sarver. It is
believed that today the Sarver switch was replaced with a Digital Loop
Carrier (DLC) junction point. According to modern documentation, there is only
one switch in the Saxonburg exchange.
Call Routing by the early 1980s
All toll calls and most
calls between exchanges uses the #1EAX switch as a tandem. Prior
to the installation of the #1EAX in 1977, the Step by Step that served the Gibsonia
ratecenter served as the tandem.
All calls whose destination was an electronic exchange or a toll call were
switched using in-band signaling (i.e. MF or Multi-Frequency) tones.
All toll calls also used MF tones. Those that routed through the #1EAX allowed you to hear the MF tones. Those through the
If you called a non working number in an exchange served by an
electronic switch, your call was
sent to a Cognetronics brand of Automated Intercept System (AIS) that resided
just off the #1AEX in Gibsonia with MF signalling tones from the #1AEX. The system read the number you
dialed and the reason why the call could not be completed. A typical
recording went like this: "The number you have dialed... xxx-xxxx is
not in service. Please call your operator for assistance. This is a
recording. Thank you." In later years, the recording was adapted to
inform users that the number was in the 412 area code.
The Step by Step systems and some recordings on the #1EAX and #2EAX systems used
"Centralized Intercept" voice recordings that told you that the
number you dialed was not in service. These recordings had a
"suffix" to tell you which switch you were on. These were in the
format of 'NPTxE' where the 'x' was usually the first digit of the
prefix (example: NPT7E was Criders Corners/Cranberry Twp.)
All calls to the Step by Step exchanges from either outside the company or from
the three "electronic" switches went through the Gibsonia
operating as a regional tandem. (I am not sure if a call originating on a
step switch and ended on another step switch had direct trunks, or
was routed via the #1EAX operating as a tandem.)
The step systems were dial pulsed via the #1EAX (used as a regional
tandem). I assume
this was done via direct trunks with interrupting current and not
in-band or out-of-band signaling. There was a very noticeable and
distinct clicking sound as it pulsed dialed. The clicking did not
start until after you dialed the first 3 digits of the prefix. You
could also hear this when you called in long distance from outside
The "clicks" were usually coded for a particular prefix. Most used a
2 digit code that MIGHT have been the last 2 digits of the prefix,
then the 4 digits of the phone number. I assume this was either the
fact that the first digit was absorbed in the switch, or it used the
Gibsonia Step by Step switch as a step tandem. The exception to the "code" was the
Freeport exchange (295) where only the last 4 digits were dialed.
Even if you were on a rotary phone (instead of Touch-Tone) it pulsed
after you dialed each digit or series of digits.
Interesting note - Early on, the Gibsonia #1EAX switch (operating as
a tandem) also pulsed
dialed long distance calls to neighboring Butler, PA (then United
Telephone) when it too was a SxS system. All of Butler County was
equipped for 911 calls. I "accidentally" found out that when you dialed
into the 284 prefix in Butler (then a mostly unpopulated prefix),
you could reach the 911 operator by dialing 284-911x (where x is any
digit). Fortunately they never figured out where the calls were
coming from... (grin)
Making long-distance calls: Before the Gibsonia #1EAX was installed,
Step by Step customers used the special DDD code of "150" to place long distance calls.
Shortly after the #1AEX was installed, all customers dialed "1" to
place long distance calls. All long distance calls made from electronic
exchanges (#1 and #2EAX) were always with a "1". Phone books from
1980 and 1981 show this dual arrangement. But by 1982, all calls were with a
Up until about 1980 or 1981, local directory assistance was 112, repair
was 113. This was served from the Gibsonia Step by Step switch.
In the Step by Step switches, there were DTMF (Touch Tone) converters on the linefinders.
This allowed Touch Tone service for all phones. (Most pay phones,
for example, were DTMF by 1982). As a result, the dial tone on the
Step by Step switches was the modern dial tone we know of today. Other
signaling tones (ringback, busy, reorder) were produced by the tone
plants at each switch.
Making calls form pay phones (circa 1982) - All pay phones served by
Step by Step switches in Allegheny county were "Coin First". Pay phones that
were served by the Wexford exchange (935) were "Dial Tone First"
since it was an electronic switch. Pay phones in Butler county were
all "Dial Tone First" regardless if it was a were a Step
by Step or
electronic switch. The reason was that Butler county had 911 service
and wanted people to be able to dial 911 without the use a coin.
Operator Services: There was no "0+" dialing at that time and all operator functions
were served from a "coardboard" operator station attached to the SxS
switch at the Gibsonia office.
Dialing into New Castle, PA (then 652, 654, 657) was done with MF
with direct trunks and was put on a noisy microwave trunk. But when
the called party answered, the noise went away and it was a clear
conversation. It could be that 2600Hz signaling was present on the
trunk but was not properly filtered.
Operators are Outsourced - Changes in 1982
1982 - In May 1982,
North Pittsburgh retired their old cordboard operator system. The
operator services were outsourced to AT&T
TSPS (Traffic Service Position Station) operator services platform in Youngstown, OH.
This also included 0+ dialed Operator-Assisted calls.
(Note - This arrangement lasted
until the mid to late 1980s, when at that time intra-LATA operator
services were changed to Bell Atlantic/Verizon - branded as North Pittsburgh
When you dialed an Operator-Assisted call, the #1EAX tandem
connected you to the Bell/AT&T operator via a long distance trunk
(via a noisy microwave link). The #1EAX tandem dialed
a string of MF digits of the number you dialed, a short pause (while
the trunk flashed or "winked" the appropriate tone), then a
string of MF digits of the area code (then 412) and the number you were
dialing from (serving as Automatic Number Identification or ANI).
In order for the pay phones to work with the TSPS platform, all pay phones in the 443 exchange were changed
from 443-98xx and 443-99xx to 443-48xx and 443-49xx respectively
(keeping the same last 2 digits as before). Prior to this time, none
of the 443-4xxx numbers were in use (a free thousands block at that
time). In addition, all other pay phones in ALL exchanges
(including Step by Step) were converted to dial-tone first and long-distance
calls were routed via the #1EAX (complete with MF signaling
with MF ANI).
Note - This arrangement lasted
until the mid to late 1980s, when at that time intra-LATA operator
services were changed to Bell
Atlantic/Verizon - branded as North Pittsburgh Telephone.
1982 - Penn
Telecom resells AT&T long distance at cheaper (bulk) rates by
developing a Feature Group "A" system (7-digit number & 5 number PIN
access) called Penn Telecom DART (Distance Area Reduced Toll)
service. When the service was first started, this was on some sort
of PBX-like system and did not have the ability to provide proper
supervision for billing purposes. Hence, each and ever call got
billed at least for 1 minute minimum, even if the called party did
not answer. (Note - when the system was moved to the DMS-100 in
1983, this problem was solved).