All-figure dialling

All-figure dialling was a telephone numbering plan introduced in the United Kingdom starting in 1966 that replaced the traditional system of using initial letters of telephone exchange names as the first part of a telephone number.^[1] The change primarily affected subscriber numbers in the cities of Birmingham, Edinburgh, Glasgow, Liverpool, London and Manchester.

The transition to all-figure dialling occurred between 1966 and 1970 and was initiated by the General Post Office. It was one of the first in a series of changes in the organisation of British telephone numbers. In most areas the change initially only affected the presentation of area codes, but in six multiple exchange director areas such as the London telephone area, the change required the introduction of new local exchange codes. The period of parallel operation of the old and new systems ended in 1970 with the ANN: All-figure Numbers Now advertising campaign. The changes were required for the continued good operation of the telephone service, but were considered controversial at the time. They occurred because of the increase in subscriber-dialled international calls from countries which used a different mapping of letters to numbers on the rotary dial and because the number of useful exchange mnemonics that were possible under the existing system was being exhausted. The implementation of all-figure dialling and new local exchange codes in director areas allowed changes to be made to routing of calls into and out of these areas.

Background

The General Post Office issued subscriber trunk dialling (STD) codes for most areas during the late 1950s and early 1960s. The codes allowed subscribers to call other exchanges directly and without the assistance of an operator. To help the public remember the new codes they were represented by a recognisable combination of two letters and a number. The letters and numbers corresponded as follows:

1	2	3	4	5	6	7	8	9	0
	ABC	DEF	GHI	JKL	MN	PRS	TUV	WXY	OQ

The three character codes were dialled after an initial '0' which gave trunk access. For example the code for Bath was BA5, which was dialled as 0225. The rotary dial included the corresponding letters next to the appropriate digits.

In six metropolitan areas around major cites, groups of multiple exchanges operated in a director telephone system. The six cities were Birmingham, Edinburgh, Glasgow, Liverpool, London and Manchester. In these areas the first three digits of the seven digit subscriber number was presented as letters chosen to represent the local exchange within the director area. For example, in the London telephone area a subscriber number on the Wimbledon exchange was presented WIM 1234 and dialled as 946 1234. These local exchange codes (introduced in London in 1927) predated the introduction of STD codes by several decades.

Problems

The continued operation of the system presented a number of problems. With the growth of subscriber dialled international calls from abroad and the incompatible allocation of letters to numbers on foreign dials, there was an increase in the number of dialling errors. In London the number of three letter codes that could be used to represent exchanges had been exhausted. Significant changes were planned to the way calls in and out of the London telephone area were to be handled that required exchange codes to be grouped together into sectors and it was not possible to implement these changes without a transition to all-figure dialling.^[2] The General Post Office produced a pamphlet All-Figure Telephone Numbers in 1965 which summarised the problems.

Changes

From 1966, UK telephone dialling codes ceased to be represented with letters. In most areas this did not require any changes to the telephone codes or numbers, e.g. the Sevenoaks STD code changed from 0SE2 to its numerical equivalent 0732. However, in Director telephone areas such as the London telephone area, the changes permitted many new exchange codes to be issued that did not correspond to letters representing the geographic locations. As '1' was also available for the 'B' and 'C' digits, this allowed many more exchange codes such as 211, 219, 221 to be used. At the same time, many local exchange codes were altered in order to group them into geographic sectors (e.g. GROsvenor became 499 rather than 470) to eliminate the need for all incoming calls to be routed via central London.

In the Director areas the old codes continued to work in parallel with new codes until 1970 when the "ANN: All-figure Numbers Now" advertising campaign prompted callers to dial only the new codes.^[3] By October 1969 in Edinburgh 79% of calls were being made using the new local exchange codes, in London 72% and in Glasgow 43%. London was the first to withdraw the ability to dial the old codes in January 1970 and from April the parallel operation was withdrawn in the other five cities.^[4]

The change to all-figure dialling was controversial and was debated in both Houses of Parliament. Among the criticisms of the new system was the perceived difficulty in remembering telephone numbers, the inability to easily recognise where a telephone number was located and the need for a change so soon after the implementation of subscriber trunk dialling.^[5]^[6]

References

↑ A R Valdar (2008). Understanding telecommunications networks. Institution of Engineering and Technology. p. 258.
↑ A R Valdar (2008). Understanding telecommunications networks. Institution of Engineering and Technology. p. 256.
↑ "Selling the network". Archived from the original on 1 January 2012. Retrieved 25 September 2012.
↑ "Glasgow response to all-figure dialling slow". The Glasgow Herald. 29 October 1969.
↑ "Lords Sitting: S.T.D. and All-Figure Dialling". Parliamentary Debates (Hansard). House of Lords. 16 March 1967.
↑ "Commons Sitting: Telephone Service (All-Figure Numbers)". Parliamentary Debates (Hansard). House of Commons. 12 May 1967.

External links

Different standards for letter-number correspondence on phone keypads

Telephone numbers in the United Kingdom
Number plan	List of dialling codes Non-geographic numbers
Number changes	All-figure dialling Area name changes Big Number Change Code misconceptions PhONEday
Special numbers	100 101 105 111 112 116000 116111 116123 118xxx 123 141 1471 150 155 1571 1572 999
Notes	Numbers above can be dialled only from within the United Kingdom. Numbers below can be dialled within the United Kingdom by prefixing with a 0 or with +44, and from outside the United Kingdom by prefixing with +44.
Geographic area codes	113 114 115 116 117 118 1200 1202 1204 1205 1206 1207 1208 1209 121 1223 1224 1225 1226 1227 1228 1229 1233 1234 1235 1236 1237 1239 1241 1242 1243 1244 1245 1246 1248 1249 1250 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1267 1268 1269 1270 1271 1273 1274 1275 1276 1277 1278 1279 1280 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 131 1320 1322 1323 1324 1325 1326 1327 1328 1329 1330 1332 1333 1334 1335 1337 1339 1340 1341 1342 1343 1344 1346 1347 1348 1349 1350 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1366 1367 1368 1369 1371 1372 1373 1375 1376 1377 1379 1380 1381 1382 1383 1384 1386 1387 13873 1388 1389 1392 1394 1395 1397 1398 1400 1403 1404 1405 1406 1407 1408 1409 141 1420 1422 1423 1424 1425 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1442 1443 1444 1445 1446 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1460 1461 1462 1463 1464 1465 1466 1467 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1487 1488 1489 1490 1491 1492 1493 1494 1495 1496 1497 1499 1501 1502 1503 1505 1506 1507 1508 1509 151 1520 1522 1524 15242 1525 1526 1527 1528 1529 1530 1531 1534 1535 1536 1538 1539 15394 15395 15396 1540 1542 1543 1544 1545 1546 1547 1548 1549 1550 1553 1554 1555 1556 1557 1558 1559 1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1575 1576 1577 1578 1579 1580 1581 1582 1583 1584 1586 1588 1590 1591 1592 1593 1594 1595 1597 1598 1599 1600 1603 1604 1606 1608 1609 161 1620 1621 1622 1623 1624 1625 1626 1628 1629 1630 1631 1633 1634 1635 1636 1637 1638 1639 1641 1642 1643 1644 1646 1647 1650 1651 1652 1653 1654 1655 1656 1659 1661 1663 1664 1665 1666 1667 1668 1669 1670 1671 1672 1673 1674 1675 1676 1677 1678 1680 1681 1683 1684 1685 1686 1687 1688 1689 1690 1691 1692 1694 1695 1697 16973 16974 16977 1698 1700 1702 1704 1706 1707 1708 1709 1720 1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1732 1733 1736 1737 1738 1740 1743 1744 1745 1746 1747 1748 1749 1750 1751 1752 1753 1754 1756 1757 1758 1759 1760 1761 1763 1764 1765 1766 1767 1768 17683 17684 17687 1769 1770 1771 1772 1773 1775 1776 1777 1778 1779 1780 1782 1784 1785 1786 1787 1788 1789 1790 1792 1793 1794 1795 1796 1797 1798 1799 1803 1805 1806 1807 1808 1809 1821 1822 1823 1824 1825 1827 1828 1829 1830 1832 1833 1834 1835 1837 1838 1840 1841 1842 1843 1844 1845 1847 1848 1851 1852 1854 1855 1856 1857 1858 1859 1862 1863 1864 1865 1866 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1882 1883 1884 1885 1886 1887 1888 1889 1890 1892 1895 1896 1899 1900 1902 1903 1904 1905 1908 1909 191 1920 1922 1923 1924 1925 1926 1928 1929 1931 1932 1933 1934 1935 1937 1938 1939 1942 1943 1944 1945 1946 19467 1947 1948 1949 1950 1951 1952 1953 1954 1955 1957 1959 1962 1963 1964 1967 1968 1969 1970 1971 1972 1974 1975 1977 1978 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1992 1993 1994 1995 1997 20 23 24 28 29
Non-geographic prefixes charged at geographic rate	300 302 303 306 308 330 331 332 333 342 343 344 345 370 371 372 373
Personal, pager, VoIP and corporate numbering	55 56 70 76
Mobile telephone prefixes	71xx 72xx 73xx 74xx 75xx 7624 77xx 78xx 79xx
Non-geographic prefixes that are free-to-caller	500 800 808
Non-geographic prefixes with additional Service Charge	842 843 844 845 870 871 872 873
Non-geographic prefixes with additional Service Charge	900 901 902 903 904 905 906 907 911 912 913
Non-geographic prefixes with additional Service Charge used for Adult services	908 909 982 983 984 989

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