Does the engineer test number 17070 still work if the PSTN line being tested has been transferred to PDPL at the local exchange?
Any reason for asking ? , I dare say the number of pre digital phone lines is still pretty small , and as it is comprised of phone only customers, the chance of someone being here on this forum ( with internet access from another source other than their ‘landline’ ) trying 17070 and confirming it works ( or not ) is slim .
FWIW , I suspect it will provide some functionality , as 17070 does with Digital Voice , although different in that it will still present -50v DC to line .