Longer messages may be sent, but technically require a continuation prefix and a sequence number on subsequent SMS messages. So one long SMS consists of two and more parts separate SMSs. Subscriber phone presents it as one message but technically they were delivered separately and were united. We don't recommend send more then 10 parts message (for GSM 03.38 it is 153*10 = 1530 characters).

@£$¥èéùìòÇ\nØø\rÅåΔ_ΦΓΛΩΠΨΣΘΞ\x1BÆæßÉ !"#¤%&\'()*+,-./0123456789:;<=>?
¡ABCDEFGHIJKLMNOPQRSTUVWXYZÄÖÑܧ¿abcdefghijklmnopqrstuvwxyzäöñüà

Everything from GSM 03.38 plus:
€ ‚ƒ„…†‡ˆ‰Š‹Œ Ž ''""•–—˜™š›¡¢£¤¥¦§¨©ª«¬®¯°±²³
´µ¶·¸¹º»¼½¾¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖ×ØÙÚÛÜÝÞßàáâãäåæçèéêëìíîïðñòóôõö÷øùúûüýþÿ

All the other characters. For example, we use that for Russian.