Intercommunication Table and Wall Telephones
Radial Selector, Single Line Local Battery, Secret System
N1641 shown
A secret system is sometimes preferred, and this range of instruments has been specially designed to give secrecy and be entirely free from "cross talk," electrostatic and magnetic induction's.
The case work is of high-class finished hardwood.
The micro-telephone is fitted with an electromagnetic receiver, "inset" transmitter and all-metal hygienic mouthpiece.
The radial selector is of substantial design, positive in action, and does not require either automatic or manual replacement, as a ring can be received with the pointer in any position.
Cards giving full working instructions and having spaces for inserting the names of stations, are supplied. Also a diagram showing how the instruments, cables and batteries are connected up.
Three cells are required at each station up to 500 feet of cable between the two most
distant stations, and four cells for over 500 feet of cable.
| No. of Lines | Code No. | Weight lbs. |
| 5 | N1640 | 6.5 |
| 10 | N1641 | 6.5 |
| 15 | N1642 | 6.5 |
| 20 | N1643 | 6.5 |
| 25 | N1644 | 6.5 |
| 30 | N1645 | 6.5 |
Overall dimensions 12 x 10 x 6 inches.
When these instruments are required as wall sets a bracket is supplied.
N1643 shown right
Intercommunication Table and Wall Telephones
Radial Selector, Single Line, Central Battery
These instruments are of exactly the same design and outward appearance as N1640 - N1645 those above, but although secrecy is not given, the circuit and working parts are so arranged that the mischievous listening-in by simply moving the selector arm over the numbers has been guarded against.
Full working instructions are provided, also a diagram showing the necessary connections for installation.
The central battery should be located as near the centre of the system as possible.
| No. of lines | Code No. | Weight lbs. | |
| 5 | N1650 | 6.5 | |
| 10 | N1651 | 6.5 | |
| 15 | N1652 | 6.5 | |
| 20 | N1653 | 6.5 | |
| 25 | N1654 | 6.5 | |
| 30 | N1655 | 6.5 |
Overall dimensions 12.5 x 10.25 x 6 inches.
NOTE - When these instruments are required as wall sets a bracket is supplied.
The radial selector, secret system and central battery system instruments are made as
table sets only.
This arrangement saves customers the necessity of keeping two distinct types in stock.
When these instruments are required to be fixed and used as wall sets we supply a bracket as illustrated.
The shelf is of the same high-class finish hardwood as the instruments. and the
supports are black enamelled iron.
Code No. N8530
Battery Boxes
To hold 3 wet or dry cells. Code No. N3230
To hold 4 wet or dry cells. Code No. N3231
Junction Boxes
| Code No. | No. of terminals | For Instruments | Dimensions ins | Weight lbs. |
| N3300 | 10 | N1601, N1611, N1640 and N1650 | 7.25 x 6 x 2 | 1.9 |
| N3301 | 16 | N1600, N1603, N1610, N1613, N1641, N1642 and N1651 | 10.25 x 6 x 2 | 2.75 |
| N3302 | 22 | N1604, N1605, N1614, N1615, N1643, N1652, N1680 and N1682 | 13.25 x 6 x 2 | 4 |
| N3303 | 28 | N1602, N1606, N1607, N1612, N1616, N1617, N1644, N1653 and N1654 | 16.25 x 6 x 2 | 5 |
| N3304 | 34 | N1608, N1608, N1618, N1618, N1645, N1655, N1681 and N1683 | 19.25l x 6 x 2 | 5.75 |
Cables for Single Line Sets
| Braided | Lead covered | ||
| Code No. | Code No. | No. of conductor pairs | For instruments |
| N3350 | N3370 | 7 | N1640 |
| N3351 | N3371 | 10 | N1601, N1611, N1650 |
| N3352 | N3372 | 14 | N1603, N1613, N1641, N1651 |
| N3353 | N3373 | 19 | N1642, N1652 |
| N3354 | N3374 | 24 | N1605, N1615, N1643, N1653 |
| N3355 | N3375 | 29 | N1607, N16I7, N1644, N1654 |
| N3356 | N3376 | 34 | N1608, N1618, N1645,N1655 |
Cables for Metallic Line Sets
| Braided | Lead covered | ||
| Code No. | Code No. | No. of conductor pairs | For instruments |
| N3360 | N3380 | 9 | N1600, N1610 |
| N3361 | N3381 | 13 | N1602, N1612, N1680 |
| N3362 | N3382 | 16 | N1681 |
| N3363 | N3383 | 21 | N1604, N16I4, N1682 |
| N3364 | N3384 | 27 | N1606, N1616 |
| N3365 | N3385 | 33 | N1608, N1618, N1683 |
The use of lead-covered cable is strongly recommended for intercommunication telephone installations.
Taken from the Ericsson catalogue, edition 26
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