TELEPHONE No. 8401
Telephone No. 8401AR is an Ambassador range telephone providing LD, MF or mixed signalling facilities and the option of earth loop, timed break recall or C Wire signalling. The signalling and recalling modes are selected by internal links not accessible to the customer. As supplied the links are set to give DEL working, mixed signalling and earth loop recall. Mixed signalling provides the facility of originating a call in the LD mode and subsequently changing to the MF mode for the duration of the call by pressing the button making, the telephone suitable for slow speed MF data applications.
For C Wire signalling it is necessary to change the instrument line cord to a six way cord
(Cord Connecting 6/524). Telephone 8401AR is suitable for table or wall mounted use, two
keyhole slots are provided in the base to facilitate wall mounting without the use of
Signalling Options Socket Pins Socket Pins MF PL4 2+3 PL6 2+3 LD PL4 2+1 PL6 1+2 Mixed PL4 2+1 PL6 2+3 Recall Options C Wire PBX PL3 1+2 PL5 2+3 Timed Break PL3 4+5 PL5 2+3 * Earth Loop PL3 2+3 PL5 1+2 * As supplied
Telephone 8401 AR each draws typically 24 micro Amps on-hook line current on a 50 volt line to retain stored number memory. This may give apparent 'Low Loop' line test conditions.
As with other modern press button telephones, the electronic keypad and transmission circuitry may appear to give High Resistance telephone loop test conditions.
The keypads of Telephones 8401 AR are line powered and required no external power supplies. Line current is drawn whilst the telephone is "on hook" to maintain stored number memory. The stored number memory will be cleared if the telephone is disconnected from line for longer than (typically) 10 minutes. There is no provision for memory retention batteries in Telephone 8401 AR.
RADIO FREQUENCY INTERFERENCE
Telephone 8401 AR is designed to incorporate good RFI immunity in the frequency range 50KHz to 200Mhz.
FIELD OF USE
Telephone 8401 AR is suitable for use where customers need to access MF signalling data services (e.g. Voicebank and Message pager services) via Loop Disconnect pulsing network but may also be used to supersede existing Ambassador Telephones, where appropriate, when direct replacements are not available.
The timed break recall facility will work satisfactorily on 70 Volt System X Lines.
Last revised: April 17, 2021