The following is a list of old Bell System (AT&T Long Lines) routing codes. These were used by Bell System/AT&T operators for various functions within the network. These are listed here for historical purposes only.
Old AT&T/Bell System Operator Routing Codes
At one time many functions that were used by AT&T/Bell System operators were accessed by dialing special codes in the toll system network. The following is a list of routing codes once used by AT&T and Bell Operating Companies (BOC) that telephone operators used to use to access certain functions on the Bell System network. These were used in the days of MF (Multi-Frequency) signaling. Most codes were accessed by dialing KP+NPA+XXX+ST where XXX= the code, except where noted. This list was provided by telephone historian Mark Cuccia (1961-2014).
000 – The Rate Quote System (RQS) (1)
001 – 005 Spare (2)
006 – 008 Reserved (3)
011 International Origination Toll Center (IOTC) (15)
014 TWX Switching Plan (Canada) (?)
015 – 071 Spare
072 – 079 Reserved
080 – 081 Spare
082 – 087 Reserved
090 – 099 Spare
100 Plant Test – balance termination
101 Plant Test – test board
102 Plant Test – Milliwatt tone (1004 Hz)
103 Plant Test – signaling test termination
104 Plant Test – 2-way transmission and noise test
105 Plant Test – Automatic Transmission Measuring System / Remote Office Test Line (ROTL)
106 Plant Test – CCSA loop transmission test
107 Plant Test – par meter generator
108 Plant Test – CCSA loop echo support maintenance
109 Plant Test – echo canceller test line
110 – 119 Operator Codes
115 Operator Leave Word
116 Inward DA
120 Network Emergency Center (?)
121 Inward Operator (9)
122 AT&T Ready line INWATS (4)
123 – 130 Reserved
131 Directory Assistance
132 – 137 Reserved
138 IDDD for Equal Access (7)
139 – 140 Reserved
141 Rate and Route (10)
142 -147 Reserved
148 points not on an NPA – Hermosillo, Mexico (5)
150 Cable Control (Satellite Avoidance) – Hawaii (5)
151 International Assistance
152 – 157 Reserved
158 Operator Assistance for Equal Access (7)
160 International Operator Center (IOC) (6)
161 Trunk Trouble Reporting
162 – 167 Reserved
168 points not on an NPA – Grenada
169 – 170 Reserved
171 points not on an NPA – Monterey, Mexico
172 points not on an NPA – Dominican Republic, Puerto Rico, Virgin Islands (Canada only)
174 Cable Control (Satellite Avoidance) Caribbean
176 points not on an NPA – Mexicali, Mexico
177 – 178 Reserved
179 points not on an NPA – Grenada
180 points not on an NPA – Mexico Numbers
181 Toll Station
182 International Switching Center (ISC) White Plains, 5 (14)
183 ISC New York, BW24
184 ISC Pittsburgh
185 ISC Atlanta OLT
186 ISC Sacramento
187 ISC Denver/Sherman Oaks (?) (15)
188 ISC New York, 5450
189 points not on an NPA – Mexico City, Mexico
190 points not on an NPA – Mexico Numbers
191 Conference loop around
191 AT&T Advanced 800 intercept recording frames (4)
193 Cable Control (Satellite Avoidance) – Grenada
194 points not on an NPA – Tijuana, Mexico
195 AT&T Advanced 800 (4)
196 AT&T International 800 (4)
198 AT&T International City Service Center (ICSC)
199 Cable Control (Satellite Avoidance) – Alaska
199 AT&T USA Direct (4)
4 or 5 digit codes (8)
1150,11501 Universal or Coin Callback
1151,11511 Conference Operator (11)
1152,11521 Mobile Service / Air-Ground
1153,11531 Marine Service (12)
1154,11541 Toll Terminal
1155,11551 Time and Charges callback
1156,11561 Hotel / Motel callback
1157,11571 IOTC access trunk
1158,11581 Inward- completion assistance (BOC)
1159,11591 Inward- busy line verification (BOC)
1160,11601 Calling Card Validation – dial pulse equipment (13)
1161,11611 Calling Card Validation – DTMF equipment
1162,11621 Calling Card Validation – MF equipment
(1) The Rate Quote System is a voice response system used by operators to obtain routing information. The system, now being phased out, was used as an alternative to calling the Rate and Route operator. Operators would key-in required routing information and a synthesized voice would respond. Though the RQS is still operational, operators now obtain routing information from COMPIS (See note 10).
KP+DD+ONPA+NXX+TNPA+NXX+ST to get the “rate step” for:
DD = 00 Now
DD = 01 Day Call (08:00-17:00)
DD = 02 Evening Call (17:00-23:00)
DD = 03 Night Call (23:00-08:00)
KP+04+? Something with Mexico, unclear.
KP+05+NPA+NXX+ST Gives the routing for a BOC inward (See note 9)
KP+06+NPA+NXX+ST gives the routing for an AT&T inward operator (See note 9)
KP+07+XXXXXXX+ST Reads back the numbers you just typed
KP+08+? Something with Enterprise and Zenith numbers, unclear.
KP+09+NPA+NXX+ST Gives you the current time for the area and exchange just dialed.
(2) When a code is marked spare, that means that there is no current or planned network wide usage. It still may be utilized as a non-standard POTS exchange for WATS service by local companies.
(3) When a code is marked reserved, it means that there may be planned network wide usage.
(4) This code is used by an AT&T custom service. It may be thought of as acting like a special area code and takes the following dialing format: KP+XXX+YYY+YYYY+ST where XXX is the code in question and Y can be any number 0-9.
(5) All “points not on an NPA” and “Cable Control” function as pseudo area codes and are followed by a telephone number.
(6) Calls to the IOC are dialed as follows: KP+160+CCC+ST CCC=Country Code (i.e. 044 or 144 for the UK).
(7) These are special codes used with Equal Access. They are as follows:
KP+138+PIC+ST then KP+CC+cc+xxxxx+ST
Where PIC is the primary carrier code, CC is the country code and cc is city code. xxxxx is subscriber number. We are not sure exactly when and where these are used.
(8) All four and five digit codes are dialed as follows:
KP+NPA+XXXX+ST or KP+NPA+XXXXX+ST.
Keep in mind that not every code is in use in every NPA.
(9) The format for an AT&T inward is usually KP+NPA+121+ST — In some small cities there is an extra code used called a Terminating Toll Centre (TTC) or sometimes just a city code. If a TTC is used, the format is KP+NPA+TTC+121+ST. To get an inward with most BOCs you dial KP+NPA+11591+ST but there are some which use a format of KP+NPA+TTC+121+ST. To get the inward routing for a particular exchange, use the Rate Quote System (RQS).
(10) The number for Rate and Route was 800+141+1212 but this was discontinued in 1987 when the TSPS operators got a computer terminal called COMPIS. In each there is an inward which acts like a Rate and Route operator. In New York it is 716+121.
(11) With the advent of Alliance Teleconferencing, use of the conference operator dwindled. There are currently four operator handling conferences. They are as follows: Atlanta 404+11511, Minneapolis 507+11511, New York 212+11511 and Oakland 415+11511. 800-225-0233 translates to the conference operator closest to you.
(12) The Marine Operator is used in calling ships that are close to the United States. There is an operator called the “High Seas” operator who can be reached by dialing 800-SEA-CALL (800-732-2255). The High Seas operator is a service of AT&T, while Marisat is an independent company. A High Seas call can go to any ocean for $14.98 for the first 3 minutes and $4.98 for each additional minute. A Marisat only to three oceans and costs $10 a minute.
(13) 116X and 116XX are used to verify an AT&T Calling Card number. You dial KP+NPA+116XX+ST when you hear a “bong” you dial the calling card number. If you use 11611 you enter the number in Touch Tone and if you use 11621 you enter the card number in MF using KP and ST.
(14) These ISC codes are used to provide alternate routing for electro-mechanical switches. Some older electro-mechanical switches, for example #5 Crossbar (5XB) cannot outpulse 011+CCC (CCC=Country Code) for international dialing. AT&T has set up these special codes to handle international calls. A 5XB can dial KP+18X+ST. They would then receive a wink (short blast of 2600 Hz) and would proceed to dial the country code and number. If you want to make an international call you dial KP+(NPA)+18X+ST where the NPA is optional. After the wink dial the country code, city code and number. The “,” after the city name is the switch number if there is more then one 4-ESS in that city.
(15) The 187 code was assigned to Atlanta until up to the end of February 1988. AT&T is in the process in routing the calls to the Sherman Oaks Office in California.
(16) To make international calls dial KP+011+CCC+ST where CCC is the country code; and then dial KP+CC+XXXXXXX+ST where CC is the city code and XXXXXXXX is the telephone number.