Telephone Call Filtering System 
                                      
   
   Blocks unwanted telephone calls
   Combats automated polling systems
   Holds over 900 telephone numbers 
   No external power connection required 
   Simple 2 Button Operation 
   Small size:100 * 61 * 22mm 
   Year 2000 compliant
   
   
   The PDA Sentry is in essence an automated telephone receptionist that
   operates 24 hours a day and makes sure that only those calls you want
   are passed through to your equipment. The unit works by examining the
   Caller Identification information* sent by your telephone exchange
   immediately prior to the actual call itself. This allows the unit to
   match the source and/or type of the call against the internally stored
   criteria and makes the decision as to whether to put the call through
   or not.
   
   This unit is designed primarily for domestic operation, blocking
   unwanted /nuisance calls and for small businesses which dont have a
   lot of nuisance / junk fax traffic The unit is ready to go with a
   default set-up to either prevent anyone withholding their telephone
   number or supplying an undialable* number from being put through to
   your equipment or telephone, which will remove the great majority of
   nuisance calls.
   * defined as numbers with invalid STD codes or STD/number combinations
   
   Most calls that are received will normally have a number associated
   with them. If during the call or after the call you want to block
   further calls from that source, simply press the BLOCK button to enter
   the number into the units memory. Over 900 telephone numbers can be
   stored in each unit.
   Numbers stored in the unit can be removed by again through the front
   panel switches.
   
   Note: Calls received from some organisations with their own telephone
   system will not have a number associated with the call and the
   Unavailable flag is set instead of Withheld. Such calls you may
   require so to block all these types of calls could be a problem. The
   unit will indicate through the front panel lights that there is no
   number and that a different call type has been received. If required
   Unavailable calls can also blocked however Sentry will override this
   command for all International or Operator calls.
   
   Fax machines, even if they are on ex-directory lines, can be
   identified and added to fax bureau lists by computer equipment which
   automatically dials every possible telephone number in a particular
   area. As such automated polling systems often use withheld telephone
   numbers to search for fax machines, Sentry will prevent such systems
   from identifying your fax machine as a possible target for junk faxes.
   
   Operation
   The unit operates before the ringing commences so even when calls are
   being blocked, no annoying ringing is heard or passed on to the
   attached equipment. The caller simply hears the ringing tone generated
   by the local exchange equipment so no indication is given to the
   caller that their call is being blocked. For maximum benefit ,use
   Sentry with either a service such as the BT Call Minder or Call
   Diversion to a separate line containing an answering machine. This way
   when the call is blocked, the telephone exchange will automatically
   divert the call to an answering machine/service. If it is a genuine
   caller, they can leave a message so you can call them back. Calls from
   salesmen for double glazing etc will not normally result in a message
   being left.
   
   Installation
   The unit comes with cable adapters to facilitate locating the unit
   between a telephone line socket and the attached equipment. No power
   connection is required as the unit operates from its own internal
   power source. The units battery power is supplemented by acquiring and
   storing power from the ring current of unwanted telephone calls. Plug
   the 2m line cord into the socket marked Line In and the stub cable
   with the BT socket into the Line Out socket
   
   Simply remove the equipment line cord from the telephone line Master
   socket and plug into the socket provided on the Sentry. Then plug the
   Sentry line cord into the Master telephone socket. Remember that if
   you do not plug the unit into the Master socket, only the attached
   phone/equipment will be subject to the blocking of calls. Other phones
   on the same circuit within the building will continue to ring as
   normal. By plugging into the Master socket all phones are protected by
   the Sentry.
   
   Fix the unit to suitable vertical surface using the Velcro tape
   provided thats all you have to do.
   
   
   Technical British Telecom SIN227 , SIN242
     Bellcore TR-NWT-000030
   Compatible with following CLI standards SR-TSV-002476
     CCA TW/P&E/312
     ETSI ETS 300 659-Parts 1, 2
     Mercury MNR 19
   
   Size (H*W*D) 100*61*22mm
   Weight (including batteries) 130gms
   Ringer Equivalence Number (REN) 0
   
   *Contact your local telephone service provider to have Caller Line
   Identification - CLI provided. For BT customers this service costs
   currently £3.40 ex VAT per quarter.