With higher diffusion of digital and radio transmission the need to connect analog telephone with the ISDN network (TA applications) or radio access network (WLL application) is more and more evident.Using the SGS-Thomson ST5088 (Programmable ISDN Analog Front End), a few external components and the monochip slic L3037 in integrated ringing configuration it is possible to obtain a complete circuit optimised for this type of application.
One of the particular advantages in using the ST5088 instead of a standard codec/filter is the possibility to use the device built in tone generator to provide all the typical tones needed in the standard analog port signalling. Moreover, by proper programming , the ST5088 can be used also to perform the CLID(CAller IDentifier) function.