Issue 2, June 1935
KEYSENDER No. 5 (KEYCALLER)
1. The "Keysender No. 5"
is a device, introduced as an alternative to the standard dial on 60-line
and larger Private Branch Exchange Switchboards to reduce the time expended by the P.B.X.
operator when dialling numbers from the switchboard. By its use, the P.B.X. operator is
free to clear down or answer other calls whilst the keysender is still transmitting the
digits which have been keyed up.
2. The keysender
consists of a box-unit, having, in the front, 10 keys of the typewriter pattern which are
labelled to correspond with the standard dial. The cover is fitted with a window, through
which a disc with lines on its outer edge can be seen. This disc revolves with the
mechanism, and thus serves as a visual indication that the keysender is engaged.
3. Circuit Arrangements
have been devised to enable the keysender to be fitted on "Switchboards AT 1810, AT
3718, AT 3796" and "Sections, Switch, B.E., C.B. Multiple No. 9."
Application for the provision of a keysender for other types of switchboard should be
referred to the Engineer-in-Chief (S1).
"Keysender No. 5FA" and "Keysender No. 5LA" are the stock descriptions
allocated to the instruments for use in non-director and director areas respectively. As
implied by the suffix letters, the instruments at present are for use only in areas in
which "Dials, Auto. Nos. 10FA and LA" are fitted. For publicity purposes, the
alternative name of "Key-caller" has been adopted.
5. Fitting Single Positions
On a single-Position P.B.X., the keysender will stand on a "Bracket, Mounting,
AX," fitted to the right-hand side of the switchboard. The bracket should be fixed so
that its back edge is in line with the hinge of the key-shelf, and its top edge is level
with the top of the key-pan.
6. Two or more Positions
When two or more Positions are fitted the keysender will stand on the right-hand side of
the key-shelf, resting partly on the adjacent Position. On the last Position of the suite,
the keysender will be fitted as in the case of a single Position.
7. Method of connexion
A connexion strip is fitted on the base of the keysender, from which 1 "Cord,
Instrument, No. 5/23B" connects the keysender to a "Plug No. 503". The
keysender is plugged into the switchboard in a similar manner another to the standard
8. Emergency dial
A standard dial "Mounting, Dial, Auto. No. 9, incomplete," is to be held at the
switchboard in a "Case No. 9" fixed to the side of the board. In the event of
the keysender developing a fault, it can be withdrawn by the operator and the standard
dial inserted in its place.
9. Emergency Dial key
A "Key No. 68" labelled EMERGENCY DIAL will be fitted at the rear of the HAND
GENERATOR key. When the keysender is replaced by a standard dial, the EMERGENCY DIAL key
must be thrown and kept in that position until the keysender is restored to service. On
completion of the dialling operation, the DIAL key associated with the cord circuit must
be restored to normal.
10. Switchboard modification
Diagram N 1093 shows e modifications necessary to enable the keysender to be connected to
"Switchboards, AT 1810, 3718 and 3796". The existing "Jack No. 710 BO"
should be retained for the exchange-line circuits, but the other apparatus made spare as a
result of the alterations should be recovered. "Sections, Switch, B.E., C.B. Multiple
No. 9" will have the cord circuits rewired to diagram AT 3652.
11. To make an outgoing call
The operator inserts a calling plug into in exchange-line jack, and, on receipt 1 of
dialling tone, throws the DIAL key associated with the cord in use and sets up the code on
the keysender by depressing the appropriate keys to their full extent. It is not essential
for the DIAL key to be restored to normal until the keysender is again required for rise.
Before, however, a further call is made, it should be verified that the disk mentioned in
para. 2 has ceased to revolve.
12. Errors in keying
A CANCEL key is not provided and, if an error is made in keying-up the number required, it
is necessary to withdraw the plug from the jack, and allow the mechanism to come to rest
before again connecting the keysender to the line.
13. Partial operation of Keys
If a digit key is partially depressed whilst the Keysender is not in use, a digit key must
be fully depressed and the Keysender allowed to come to rest before it is brought into