From the NZVRS Bulletin:
IDENTIFICATION OF PRE-WAR PHILIPS RECEIVERS SOLD IN NEW ZEALAND
The first system of model identification, used on Philips receivers manufactured* between 1928 and 1931, consisted of a plain four-figure number, e.g. 2510, 2514.
Commencing in 1931 a three-figure model number combined with a suffix A, B, or C came into use. The suffix indicated the power supply source needed, thus A = AC mains, B = batteries, C = DC mains.
With the Introduction of AC/DC or 'universal' models in 1935 the suffix 'U' came into use to identify this class or receiver. Car radios, which were also introduced in 1935, initially carried the suffix 'B', as used on battery sets. Commencing in 1940 the suffix 'V' replaced 'B' for both car radios and vibrator-operated home radios, e.g. 258V, 644V.
The suffix 'AX' Indicated that a particular AC model was wired for optional use In conjunction with a separate vibrator unit, e.g 758AX. Although there were other suffixes in use overseas they are not of interest to N.Z. collectors.
Quite apart from the receivers mentioned above, there were also small numbers of Australian made sets Imported between 1938** and 1929. These were made by Thom & Smith Melbourne and usually carried a three-figure style of model numbering.
Then there were several models made during 1935-36 by Radio Corporation of N. Z. before the establishment of Philips' own factory. These usually carried a 3-figure model used In conjunction with the letter 'P' as a prefix or a suffix, e.g P636.
Receivers made by Philips were also sold under the Mullard name In the U.K. and in N.Z.. Such sets first appeared appeared in the U.K. in 1935 but were not seen in N.Z. until 1937. The two-year gap occurred during a time when the Mullard agency changed hands, the new agents being C & A Odlin Ltd. It should be noted that no sets made by Radio Corp for Philips were marketed under the Mullard name. Similarly no Australian Mullard sets (made by Airzone) were marketed in N.Z. Only three Australian Philips (made by Tazma) were marketed here under the Mullard name by Odlin's. These were models 528V, 628V and 628B, all of which were battery operated.
* Note: these models were manufactured overseas and imported for sale here, they are not, strictly speaking, NZ models.
** Typo? 1928-29?