pub fn encode_tbcd(digits: &str) -> Vec<u8> ⓘExpand description
Encode decimal digits as TBCD (telephony BCD): two digits per octet, low nibble first,
odd counts padded with the filler 0xF. Used for IMSI, MSISDN and IMEI.
Non-digit characters are dropped rather than encoded — an IMSI is digits by definition.